Document:

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                 FIRST AMENDMENT TO REVOLVING CREDIT AGREEMENT
                ----------------------------------------------

     This FIRST AMENDMENT TO REVOLVING CREDIT AGREEMENT (this "Amendment") is
made as of the 18th day of July, 2000 by and between SAUL HOLDINGS LIMITED
PARTNERSHIP, a Maryland limited partnership and SAUL SUBSIDIARY II LIMITED
PARTNERSHIP, a Maryland limited partnership (hereinafter collectively called
"Borrower"), each having its principal place of business at 8401 Connecticut
Avenue, Chevy Chase, Maryland 20815, and U.S. BANK NATIONAL ASSOCIATION, a
national banking association ("Agent") as agent for itself and for the other
financial institutions (collectively, the "Lenders") which may in the future
become parties to that certain Amended and Restated Intercreditor Agreement of
even date herewith (the "Intercreditor Agreement"), with its head office at U.S.
Bank Place, 601 Second Avenue South, MPFP 0509, Minneapolis, Minnesota 55402-
4302.

                                  WITNESSETH:
                                  -----------

     WHEREAS, the Borrower and the Agent are parties to that certain Revolving
Credit Agreement dated as of October 1, 1997 (the "Credit Agreement";
capitalized terms used and not otherwise defined in this Amendment shall have
the respective meanings assigned to them in the Credit Agreement) pursuant to
which U.S. Bank National Association ("US Bank"), BHF - Bank Aktiengesellschaft
("BHF") and Star Bank, N.A., predecessor in interest to Firstar Bank, N.A
("Firstar") have made a revolving line of credit loan available to Borrower in
the maximum principal amount of Sixty Million and 00/100ths Dollars
($60,000,000.00) (the "Loan");

     WHEREAS, concurrently herewith BHF shall be repaid in full and shall no
longer be a "Lender" under the Loan and Wells Fargo Bank, National Association
("Wells Fargo"; collectively with US Bank, Firstar and their respective
successors and permitted assigns, the "Lenders") shall be substituted for BHF as
a "Lender" under the Loan;

     WHEREAS, the Borrower has requested and the Lenders have agreed, among
other things, to increase the principal amount of the Loan to Seventy Million
and 00/100ths Dollars ($70,000,000.00) and to modify the terms and conditions
thereof in certain other respects, all as more particularly set forth herein;

     NOW THEREFORE, in consideration of the premises contained herein, and for
other good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, the parties hereto agree as follows:

1.   Incorporation of Recitals; Defined Terms.  The foregoing recitals are
     ----------------------------------------
incorporated into this Amendment by this reference as if fully set forth herein.
All capitalized terms not otherwise defined herein shall have the meaning
ascribed thereto in the Credit Agreement.

2.   Amendments to Credit Agreement.
     ------------------------------

     The Credit Agreement is hereby amended as follows:

                                       1
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     (a) Amendments to Definitions in the Credit Agreement.  Each of the
         -------------------------------------------------
following definitions currently contained in the Credit Agreement is deleted in
its entirety, and the following is inserted in lieu thereof:

          Applicable Margin:  With respect to:
          -----------------

          (a) Reference Rate Advances - 0.00%.

          (b) Eurodollar Rate Advances - shall vary as follows:

              (i)   1.625%, effective upon Agent's determination in its sole
     discretion, on the first day of each fiscal quarter for purposes of
     determining the Applicable Margin for such quarter, that the Leverage Ratio
     is not greater than fifty percent (50%) and the Adjusted EBITDA/Debt
     Service Coverage Ratio is not less than 1.80 and continuing thereafter for
     so long as such tests are satisfied, as determined by Agent; and

              (ii)  1.750%, effective upon Agent's determination, in its sole
     discretion, on the first day of each fiscal quarter for purposes of
     determining the Applicable Margin for such quarter, that the Leverage Ratio
     is not greater than fifty-five percent (55%) and the Adjusted EBITDA/Debt
     Service Coverage Ratio is not less than 1.70 and continuing thereafter for
     so long as such tests are satisfied, as determined by Agent; and

              (iii) 1.875% at all other times (subject to the provisions of
     Section 1.2(C) of this Agreement).

          Approved Asset:  An Unencumbered Asset which has been approved by
          --------------
     Lenders pursuant to Section 2.B.2 and, which, with respect to Unencumbered
     Assets submitted for approval by the Lenders from and after July 18, 2000,
     must be owned in fee simple by Borrower.

          Capitalization Value:  For any period of determination, an amount as
          --------------------
     determined by Agent in its sole discretion, equal to the sum of (a) the
     aggregate Adjusted EBITDA for the previous four calendar quarters, divided
     by nine and one-half percent (9.5%) (provided that, with respect to Real
     Estate Assets which Borrower has owned for more than three (3) months but
     less than one (1) year, as of the Calculation Date, Adjusted EBITDA shall
     be annualized based upon the period of time Borrower has owned them); (b)
     100% of the value of Unrestricted Cash and Cash Equivalents; (c) with
     respect to Real Estate Assets Under Development, including those projects
     which have been operating for less than one year, the greater of (x) 100%
     of the aggregate costs incurred and paid to the Calculation Date by the
     Borrower or (y) Adjusted EBITDA (provided that, with respect to Real Estate
     Assets which have been in operation for less than one (1) year, as of the
     Calculation Date, Adjusted EBITDA shall be

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     annualized based upon the most recent three-month period) divided by nine
     and one-half percent (9.5%); (d) 50% of the Acquisition Costs with respect
     to Real Estate Assets which, as of the date of calculation, Borrower has
     owned for less than three (3) months and (e) contractual purchase price of
     any property subject to a purchase obligation, repurchase obligation or
     forward commitment, which obligation at such time could be specifically
     enforced by the seller, but only to the extent such obligations are
     included in the definition of Total Adjusted Outstanding Indebtedness or
     Total Adjusted Committed Indebtedness, as appropriate.

          EBITDA:  For any period of determination, an amount equal to
          ------
     Borrower's earnings and Borrower's pro rata share of earnings of Borrower's
     unconsolidated subsidiaries, the unconsolidated subsidiaries of the general
     partners of Borrower, and joint ventures in which Borrower and/or
     Borrower's general partners is a party, and before interest, taxes,
     depreciation and amortization, all as calculated in accordance with GAAP,
     as determined by Agent.

          Guaranty:  The Guaranty dated as of October 1, 1997, as amended
          --------
     pursuant to that certain First Amendment to Guaranty dated as of July 18,
     2000 executed and delivered by Guarantor to Agent on behalf of the Lenders
     to guaranty the Loan, as the same may be amended, modified or replaced from
     time to time.

          Maturity Date:  July 17, 2003 unless extended pursuant to the terms of
          -------------
     Section 1.14.

          Minimum Lease Up Requirement:  Any Real Estate Asset that on any date
          ----------------------------
     of determination has been improved with a building or buildings which have
     an aggregate average occupancy of all building(s) in such Real Estate Asset
     of not less than 50% for the fiscal quarter most recently ended, other than
     Cross Town Business Center in Tulsa, Oklahoma and except as otherwise
     approved by Agent.  For purposes of this definition, a tenant shall be
     deemed to be in "occupancy" if such tenant or its subtenant(s) is in
     possession of the leased premises and such tenant is paying stipulated
     rent, if any; provided, however, when determining whether the Minimum Lease
     Up Requirement has been satisfied pursuant to Section 2.B.2 hereof, a
     tenant shall be deemed to be in occupancy if, within six (6) months prior
     to the date of determination, such tenant entered into a lease for space in
     the Real Estate Asset which such tenant previously did not occupy and there
     exists no default under such lease and no material contingencies to such
     tenant's occupancy under the lease other than completion of tenant
     improvement work.

          Note:  The Unsecured Revolving Promissory Notes dated July __, 2000
          ----
     executed and delivered by Borrower to Lenders in the maximum principal
     amount of Seventy Million and 00/100ths Dollars

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     ($70,000,000.00), to evidence the Loan, as the same may be amended,
     modified or replaced from time to time.

          Permanent Loan Estimate: For any period of determination, a
          -----------------------
     determination by Agent of a hypothetical principal amount of indebtedness
     which Borrower could incur assuming (i) payments of annual debt service
     equal to Unencumbered Adjusted EBITDA measured with respect to the Approved
     Assets only divided by 1.50, (ii) an interest rate equal to two and one-
     quarter percent (2.25%) in excess of the then-current annual yield on ten-
     year United States Treasury obligations issued most recently prior to such
     date and (iii) a twenty five (25) year principal amortization schedule.

          Revolving Commitment Amount:  Seventy Million and No/100ths Dollars
          ---------------------------
     ($70,000,000.00).

          Total Adjusted Outstanding Indebtedness:  As of any date of
          ---------------------------------------
     determination, the sum as determined by Agent of all obligations,
     contingent and otherwise of the Borrower and Borrower's pro rata share of
     all obligations of Borrower's unconsolidated subsidiaries, the
     unconsolidated subsidiaries of the general partners of Borrower, and joint
     ventures in which Borrower and/or Borrower's general partners is a party,
     whether secured or unsecured, that in accordance with GAAP should be
     classified upon the obligor's balance sheet as liabilities, or to which
     reference should be made by footnotes thereto, including in any event and
     whether or not so classified:  (a) all debt and similar monetary
     obligations, whether direct or indirect (excluding trade payables and other
     operating expenses paid by Borrower within sixty days); (b) all liabilities
     secured by any mortgage, pledge, security interest, lien, charge, or other
     encumbrance existing on property owned or acquired subject thereto, whether
     or not the liability secured thereby shall have been assumed; (c) all
     guarantees for borrowed money, endorsements and other contingent
     obligations, whether direct or indirect, in respect of indebtedness or
     obligations of others, including any obligation to supply funds (including
     partnership obligations and capital requirements) to or in any manner to
     invest in, directly or indirectly, the debtor, to purchase indebtedness, or
     to assure the owner of indebtedness against loss, through an agreement to
     purchase goods, supplies, or services for the purpose of enabling the
     debtor to make payment of the indebtedness held by such owner or otherwise,
     and the obligations to reimburse the issuer in respect of any letters of
     credit; (d) preferred stock outstanding or a similar type of investment;
     and (e) all liability under forward equity arrangements and Forward
     Purchase Contracts which at such time could be specifically enforced by the
     Seller thereunder.

     (b) Additional Definitions.  The following additional definitions are
         ----------------------
hereby inserted where appropriate in the "Definitions" Section of the Credit
Agreement:

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          Arrangement Fee.  The arrangement fee referred to in the Fee Letter.
          ---------------

          Commitment Fee.  The commitment fee referred to in the Fee Letter.
          --------------

          Fee Letter.  The fee letter dated as of July 18, 2000, between the
          ----------
     Borrower and U.S. Bank, as Agent.

          Forward Purchase Contract. A purchase agreement entered into by the
          -------------------------
     Borrower for the fee or leasehold purchase of a retail, office or
     industrial real estate property to be constructed.

          Subsidiary: For any entity, any corporation, partnership or other
          ----------
     entity of which at least a majority of the securities or other ownership
     interests having by the terms thereof ordinary voting power to elect a
     majority of the board of directors or other persons performing similar
     functions of such corporation, partnership or other entity (without regard
     to the occurrence of any contingency) which is at the time directly or
     indirectly owned or controlled by such entity or one or more subsidiaries
     of such entity or by such entity and one or more subsidiaries of such
     entity.

          Total Adjusted Committed Indebtedness: As of any date of
          -------------------------------------
     determination, the sum as determined by Agent of all committed obligations,
     contingent and otherwise of the Borrower and Borrower's pro rata share of
     all committed obligations of Borrower's unconsolidated subsidiaries, the
     unconsolidated subsidiaries of the general partners of Borrower, and joint
     ventures in which Borrower and/or Borrower's general partners is a party,
     whether secured or unsecured, that in accordance with GAAP, if fully
     funded, would be classified upon the obligor's balance sheet as
     liabilities, or to which reference should be made by footnotes thereto,
     including in any event and whether or not so classified:  (a) the committed
     amount of all debt and similar monetary obligations, whether direct or
     indirect (excluding trade payables and other operating expenses paid by
     Borrower within sixty days); (b) the committed amount of all liabilities
     secured by any mortgage, pledge, security interest, lien, charge, or other
     encumbrance existing on property owned or acquired subject thereto, whether
     or not the liability secured thereby shall have been assumed; (c) the
     maximum liability which Borrower could incur under all guarantees for
     borrowed money, endorsements and other contingent obligations, whether
     direct or indirect, in respect of indebtedness or obligations of others,
     including any obligation to supply funds (including partnership obligations
     and capital requirements) to or in any manner to invest in, directly or
     indirectly, the debtor, to purchase indebtedness, or to assure the owner of
     indebtedness against loss, through an agreement to purchase goods,
     supplies, or services for the purpose of enabling the debtor to make
     payment of the indebtedness held by such owner or otherwise, and the
     obligations to

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     reimburse the issuer in respect of any letters of credit; (d) preferred
     stock outstanding or a similar type of investment; and (e) all liability
     under forward equity arrangements and Forward Purchase Contracts which at
     such time could be specifically enforced by the seller thereunder.

     (c) Permitted Uses.  The first paragraph of Section 1.1 is deleted in its
         --------------
entirety and the following is inserted in lieu thereof:

          Upon the terms and subject to the conditions set forth in this
     Agreement, each Lender severally agrees to lend to Borrower, through the
     Agent,  an amount up to such Lender's Commitment Percentage of Advances on
     a revolving basis, at any time and from time to time, in accordance with
     the terms hereof, from the Closing Date to the Termination Date, during
     which period Borrower may borrow, repay and reborrow in accordance with the
     terms hereof, for the purpose of funding pre-development, development,
     acquisitions, renovations/expansions and short-term working capital
     (including dividend payments from Saul Centers, Inc. and distributions from
     the Borrower not to exceed $10 million in the aggregate at any one time),
     principal amortization requirements and letters of credit issued for the
     account of Borrower (up to $2.5 million per development project and not to
     exceed $10 million in the aggregate at any one time); provided, however,
     that (A) at no time shall any Lender be obligated to lend to Borrower more
     than its Commitment Percentage of the total amount of proceeds of the Loan
     which Borrower has then qualified to receive hereunder, and (B) the amount
     of the Total Revolving Outstandings shall never exceed the lesser of (x)
     the Revolving Commitment Amount and (y) the Loan Availability.  In no event
     shall Borrower use Loan proceeds in connection with the acquisition of
     unentitled land (i.e., land with none of the following:  (i) existing or
     approved infrastructure, (ii) access or entitlement to utilities or (iii)
     plan for development), mortgages or public or private securities (other
     than the purchase of shares in Saul Centers, Inc. with a value of $5
     million in the aggregate at any one time).

     (d) Number of Eurodollar Rate Fixings.  The following sentence is added at
         ---------------------------------
the end of Section 1.3 of the Credit Agreement:  "Notwithstanding anything to
the contrary contained herein, Borrower may not elect to have more than five (5)
Eurodollar Rate Advances outstanding at any one time."

     (e) Change in Non-Usage Fee.  The following paragraph is inserted at the
         -----------------------
end of Section 1.6 of the Credit Agreement:

          Notwithstanding the foregoing, from and after July 18, 2000, the non-
     usage fee shall be reduced to 0.25% per annum of the unadvanced Revolving
     Commitment Amount (after deducting the undrawn amount of any Letters of
     Credit outstanding hereunder); provided, however such percentage shall be
     further reduced to 0.20% per annum if as of the last day of the previous
     quarter the Leverage Ratio is not greater than fifty-

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     five percent (55%) and the Adjusted EBITDA/Debt Service Coverage Ratio is
     not less than 1.70.

     (f)  Change in Extension Fee.  Section 1.14(A) of the Credit Agreement is
          -----------------------
deleted in its entirety and the following is inserted in lieu thereof:

          A. Payment by Borrower on or before the first day of the Extension
     Period of an extension fee in Immediately Available Funds, as more
     particularly set forth in the Fee Letter;

     (g)  Change in Maturity Date.   The last paragraph of Section 1.14 is
          -----------------------
deleted in its entirety and the following is inserted in lieu thereof:

          Notwithstanding Borrower's right to extend the Maturity Date as set
     forth above, Borrower hereby agrees that Lenders shall have no commitment
     or obligation to extend the Maturity Date beyond July 17, 2003 unless each
     of the foregoing conditions shall have been satisfied.

     (h)  Limitation on Letters of Credit Issued in Connection with Development
          ---------------------------------------------------------------------
Projects.  The following sentence is inserted at the end of Section 2.A.1 of the
--------
Credit Agreement: "and (d) the Maximum Drawing Amount with respect to all
Letters of Credit issued with respect to a particular development project shall
not exceed $2.5 million."

     (i)  Change in Determination of Loan Availability.
          --------------------------------------------

          (I)  Section 2.B.3(A) of the Credit Agreement is hereby deleted in its
entirety and the following is inserted in lieu thereof:

               A.  Unencumbered Adjusted EBITDA for the previous four (4)
     quarters attributable to the Approved Assets (x) multiplied by sixty
     percent (60%) and (y) divided by nine and one half percent (9.5%).

          (II) The paragraph beginning "provided, however" in Section 2.B.3 of
the Credit Agreement is hereby deleted in its entirety and the following is
inserted in lieu thereof:

               provided, however, Loan Availability shall be reduced on a dollar
     for dollar basis by (x) the face amount of any Letters of Credit issued by
     Agent and outstanding hereunder, (y) the amount of any Imposition, Lien or
     Encumbrance arising with respect to any Approved Asset until same is paid
     in full, discharged or bonded over to the satisfaction of the Lenders, and
     (z) any other unsecured indebtedness of Borrower or Guarantor.

     (j)  Additional Restrictions on Guarantor.  The second to last sentence of
          ------------------------------------
Section 5.6 is hereby deleted in its entirety, and the following is inserted in
lieu thereof:

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     Borrower shall cause Guarantor at all times to (x) maintain its existence
     as a qualified real estate investment trust (a "REIT") within the meaning
     of the Internal Revenue Code and not to take any action which could lead to
     its disqualification as a REIT, (y) except with the prior written consent
     of Agent, not to be unreasonably withheld cause its shares to be listed and
     admitted to trading on the New York Stock Exchange or a successor stock
     exchange and (z) maintain its existence as a Maryland corporation.

     (k)  Change in Portfolio Loan to Value Financial Covenant.  Section 5.8(B)
          ----------------------------------------------------
of the Credit Agreement is hereby deleted in its entirety and the following is
inserted in lieu thereof:

          B.  Portfolio Loan to Value.  As of the end of each fiscal quarter and
     any other Calculation Date, Borrower shall provide evidence to Agent that
     the ratio of Total Adjusted Outstanding Indebtedness to Capitalization
     Value does not exceed sixty percent (60%).

     (l)  Change in Restriction on Fixed Rate Debt.
          ----------------------------------------

          (I)  The first sentence of Section 5.8(E) is hereby deleted in its
entirety and the following is inserted in lieu thereof:  "Borrower covenants and
agrees that not less than seventy percent (70%) of Total Adjusted Committed
Indebtedness (other than the Loan, with respect to which only the principal
outstanding on the date of calculation shall be included) shall (x) accrue
interest at a fixed rate of interest and (y) have an initial term of not less
than five (5) years."

          (II) The references in Section 5.8(E) to "$60 million" are hereby
amended to refer to "$70 million."

     (m)  Change in Restriction on Payout Ratio. Section 5.8(F) of the Credit
          -------------------------------------
Agreement is hereby deleted in its entirety, and the following is inserted in
lieu thereof:

          F.  Payout Ratio.  Distributions shall not exceed ninety five percent
     (95%) of Funds from Operation with respect to the Borrower and the
     Guarantor on a consolidated basis.

     (n)  Additional Covenants Regarding Business Operations.
          --------------------------------------------------

          (I)  The following is hereby inserted at the end of Section 5.9(D) of
the Credit Agreement:

               Each Borrower further covenants and agrees to continue to operate
     the business of such entity in substantially the same fashion as currently
     in effect, including, without limitation, acquiring Real Estate Assets of
     the same quality as the Real Estate Assets currently owned by such Borrower
     and operating and maintaining such Real Estate Assets in

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     substantially the same manner and with the same standard of care and
     quality as is currently employed by such Borrower.

          (II)  The following Section 5.9(E) is hereby inserted after Section
5.9(D) of the Credit Agreement

                (E) Within thirty (30) days of any entity becoming a Subsidiary
     of either Borrower, Borrower shall deliver to Agent each of the following
     in form and substance satisfactory to the Agent: (a) a Guaranty executed by
     such Subsidiary, pursuant to which the Subsidiary guaranties the full and
     prompt payment and performance of all of the obligations of Borrower under
     the Loan and (b) the items listed in Sections 2.B.1(C) through (H) with
     respect to such Subsidiary; provided, however, if such Subsidiary is
     expressly prohibited from becoming a guarantor of the Loan pursuant to a
     written agreement with a third party financial institution making a loan to
     such Subsidiary (the "Third Party Loan"), then, such Subsidiary shall not
     be required to enter into a Guaranty of the Loan until such time as the
     Third Party Loan has been repaid in full or the documents evidencing such
     Third Party Loan no longer contain such a restriction.

     (o)  Additional Defaults Relating to Existence of Guarantor.  The following
          ------------------------------------------------------
is hereby inserted at the end of Section 6.1(M) prior to the semicolon:

     or Guarantor shall amend its articles of incorporation without the prior
     written consent of Agent (except as may be expressly required by law or
     regulation) or Guarantor shall fail to (x) maintain its existence as a
     qualified REIT within the meaning of the Internal Revenue Code, (y) except
     with the prior written consent of Agent, not to be unreasonably withheld
     cause its shares to be listed and admitted to trading on the New York Stock
     Exchange or a successor stock exchange at any time or (z) maintain its
     existence as a Maryland corporation

     (p)  Remedies of Lenders.   Section 6.2 of the Credit Agreement is hereby
          -------------------
deleted in its entirety, and the following is inserted in lieu thereof:

          6.2  Rights and Remedies.  Upon the occurrence of an Event of Default,
               -------------------
     unless such Event of Default is subsequently waived in writing by Agent on
     behalf of Lenders, Agent, acting on behalf of the Lenders, shall be
     entitled to exercise any or all of the following rights and remedies,
     consecutively or simultaneously, and in any order:

               A.  Agent may, on behalf of the Lenders, make one (1) or more
     further Advances, without liability on the part of the Lenders to make any
     subsequent Advances.

                                       9
<PAGE>

               B.  Agent may, on behalf of Lenders, suspend the obligation of
     the Lenders to make Advances under this Agreement, without notice to
     Borrower.

               C.  Subject to the provisions of Sections 2.A.9 and 2.A.10, Agent
     may, on behalf of Lenders, terminate the obligation of the Lenders to make
     Advances under this Agreement, and declare the entire unpaid principal
     balance of the Advances made under this Agreement and all Reimbursement
     Obligations to be immediately due and payable, together with accrued and
     unpaid interest on such Advances, without notice to or demand on Borrower.

               D.  Agent may terminate its obligation to issue, extend or renew
     Letters of Credit.

               E.  Agent may, on behalf of Lenders, exercise any or all remedies
     specified herein and/or in the other Loan Documents, and/or any other
     remedies available at law, in equity or under statute.

               F.  Agent, on behalf of Lenders, may cure the Event of Default on
     behalf of Borrower.

               G.  Borrower hereby irrevocably authorizes Lenders, subject to
     the provisions of the Intercreditor Agreement, to set off any sum due to or
     incurred by Lenders against all deposits and credits of Borrower with, and
     any and all claims of Borrower against, Lenders.  Such right shall exist
     whether or not Agent on behalf of Lenders, shall have made any demand
     hereunder or under any other Loan Document, whether or not said sums, or
     any part thereof, or deposits and credits held for the account of Borrower
     is or are matured or unmatured, and regardless of the existence or adequacy
     of any collateral, guaranty or any other security, right or remedy
     available to Agent. Agent agrees that, as promptly as is reasonably
     possible after the exercise of any such setoff right, Agent shall notify
     Borrower of the exercise of such setoff right; provided, however, that the
     failure of Agent to provide such notice shall not affect the validity of
     the exercise of such setoff rights.  Nothing in this Agreement shall be
     deemed a waiver or prohibition of or restriction on Lenders to all rights
     of banker's lien, setoff and counterclaim available pursuant to law.

     In addition, upon the occurrence of any event described in Section 6.1(F)
     hereof which will not become an Event of Default prior to the expiration of
     some period of time, Agent may, on behalf of Lenders, the obligations of
     Lenders to fund Advances hereunder immediately upon the occurrence of said
     event.

     (q)  Expenses of Syndication.  Borrower hereby agrees that in addition to
          -----------------------
the fees and costs payable by Borrower pursuant to the provisions of the Credit

                                       10
<PAGE>

Agreement, as amended hereby, Borrower shall pay the expenses directly incurred
by Agent in connection with the syndication of the Loan.

3.   Commitment Fee.  On the date hereof, Borrower shall pay to Agent in
     --------------
Immediately Available Funds the Arrangement Fee and the Commitment Fee, as more
particularly described in the Fee Letter.

4.   Conditions Precedent.  The following are conditions precedent to Lenders
     --------------------
obligations under this Amendment:

     (a) Agent has received and approved a certification from each Borrower
regarding any changes in the organizational documents of Borrower and Guarantor,
together with copies of any such amendments or modifications, a resolution for
each Borrower and Guarantor authorizing this transaction, certificates of good
standing relating to each Borrower and Guarantor in the jurisdiction of
formation and an opinion of counsel for each Borrower and Guarantor satisfactory
to Agent, dated as of the date of this Amendment, and relating to such matters
with respect to this Amendment and the transaction contemplated hereby as Agent
may reasonably request;

     (b) Agent has received executed originals of this Amendment, substitute
Notes in the increased Loan amount, a First Amendment to Guaranty executed by
Guarantor, Sworn Statement and Agreement concerning Guarantees, Contingent
Liabilities and Financial Statements executed by each Borrower and Guarantor a
Compliance Certificate in the form of Exhibit B-1 attached to the Credit
Agreement (Request for Advance) and any and all other documents and agreements
which are required by this Amendment or by any other Loan Document, each in form
and content acceptable to Agent; and

     (c) Reimbursement to Agent by Borrower of their respective costs and
expenses incurred in connection with this Amendment and the transactions
contemplated hereby, including, without limitation, title costs, recording fees
(but not recording or transfer taxes), attorneys' fees, appraisal, engineers'
and inspection fees and documentation costs and charges, whether such services
are furnished by employees or agents of Agent or Lenders or by independent
contractors.

5.   Representations and Warranties.  Borrower hereby represents and warrants
     ------------------------------
that no default, Event of Default, breach or failure of condition has occurred,
or would exist with notice or the lapse of time or both, under any of the Loan
Documents (as modified by this Amendment) and that all representations and
warranties herein, in the Credit Agreement and in the other Loan Documents are
true and correct, which representations and warranties shall survive execution
of this Amendment.

6.   Ratification of Loan Documents.  Except as expressly provided herein,
     ------------------------------
nothing in this Amendment shall alter or affect any provision, condition, or
covenant contained in the Credit Agreement, the Note or in any other Loan
Document or affect or impair any rights, powers, or remedies of Agent or
Lenders, it being the intent of the parties hereto that the provisions of the
Credit Agreement, the Note and the other

                                       11
<PAGE>

Loan Documents shall continue in full force and effect except as expressly
modified hereby. All of the terms and conditions of the Loan Documents are
hereby ratified and confirmed for all purposes and in all respects. Each
reference in the Credit Agreement to "this Agreement," "hereunder," "hereof,"
"herein" or words of like import, and each reference in the other Loan Documents
to the Credit Agreement, shall mean and be a reference to the Credit Agreement
as amended by this Amendment.

7.   No Novation of Note.  Neither this Amendment nor anything contained herein
     -------------------
shall be construed as a substitution or novation of the Borrower's indebtedness
to the Lenders, which shall remain in full force and effect, as hereby
confirmed, modified, supplemented, substituted and restated.

8.   Miscellaneous.  The headings used in this Amendment are for convenience
     -------------
only and shall be disregarded in interpreting the substantive provisions of this
Amendment. Time is of the essence of each term of the Loan Documents, including
this Amendment.  If any provision of this Amendment or any of the other Loan
Documents shall be determined by a court of competent jurisdiction to be
invalid, illegal or unenforceable, that portion shall be deemed severed from
this Amendment and the remaining parts shall remain in full force as though the
invalid, illegal, or unenforceable portion had never been a part thereof.

9.   Integration; Interpretation.  The Loan Documents, including this Amendment,
     ---------------------------
contain or expressly incorporate by reference the entire agreement of the
parties with respect to the matters contemplated herein and supersede all prior
negotiations. The Loan Documents shall not be modified except by written
instrument executed by all parties.

10.  Execution in Counterpart.  This Amendment, and other Loan Documents which
     ------------------------
expressly so provide, may be executed in any number of counterparts, each of
which when executed and delivered will be deemed to be an original and all of
which, taken together, will be deemed to be one and the same instrument.

                        [Signatures on following pages]

                                       12
<PAGE>

     IN WITNESS WHEREOF, the undersigned have duly executed this Amendment as a
sealed instrument as of the date first set forth above.

WITNESS/ATTEST:           SAUL HOLDINGS LIMITED
                          PARTNERSHIP, a Maryland limited
                          partnership

                          By:  Saul Centers, Inc., a Maryland corporation, its
                               sole general partner

----------------------         By:
                                   --------------------------------------
                                   Name:
                                        ---------------------------------
                                   Its:
                                        ---------------------------------

WITNESS/ATTEST:           SAUL SUBSIDIARY II LIMITED
                          PARTNERSHIP, a Maryland limited
                          partnership

                          By:  Saul Centers, Inc., a Maryland
                               corporation, its sole general partner

----------------------         By:
                                   --------------------------------------
                                   Name:
                                        ---------------------------------
                                   Its:
                                        ---------------------------------

                                       13
<PAGE>

                              [SIGNATURE PAGE TO
                FIRST AMENDMENT TO REVOLVING CREDIT AGREEMENT]

                                U.S. BANK NATIONAL ASSOCIATION, Agent

                                By:
                                   --------------------------------------
                                   Name:
                                        ---------------------------------
                                   Its:
                                        ---------------------------------

                                       14<PAGE>
                                                                   Exhibit 10.10

                                LEASE AGREEMENT
                                ---------------

         THIS LEASE, dated as of November 9, 2000, is by and between
    DTC ASSOCIATES, LLC, a Virginia limited liability company ("Landlord")
         and LIFEMINDERS.COM, INC., a Delaware corporation ("Tenant").

                             W I T N E S S E T H :

  1. PRINCIPAL TERMS. Capitalized terms, first appearing in quotations in this
     ---------------
Section, elsewhere in the Lease or any Exhibits, are definitions of such terms
as used in the Lease and Exhibits and shall have the defined meaning whenever
used.

     1.1  "BUILDING":              Dulles Executive Plaza I, 13530 Dulles
                                   Technology Drive, Herndon, Virginia,
                                   consisting of approximately 189,701 rentable
                                   square feet of space, as measured and
                                   verified pursuant to Paragraph 1 of the
                                   Addendum.

     1.2  "PREMISES":              Approximately 131,841 rentable square feet
                                   consisting of floors 6, 5, 4 and 3, as
                                   measured, confirmed, and adjusted if
                                   necessary pursuant to Paragraph 1 of the
                                   Addendum attached hereto.  That portion of
                                   the Premises consisting of 65,799 rentable
                                   square feet of space consisting of floors 6
                                   and 5 shall be referred herein and depicted
                                   on Exhibit A as "Phase I" and the remaining
                                   66,042 rentable square feet of space (floors
                                   4 and 3) shall be referred herein and
                                   depicted on Exhibit A as "Phase II".

                                   Suite # 500

     1.3  "INITIAL TERM":          10 years, 4 months from the
                                        Anticipated Commencement Date*
                                   Anticipated "Commencement Date":
                                        September 18, 2000
                                   Anticipated "Expiration Date":
                                        January 31, 2011
                                   *[SEE SECTION 3 & 5 OF LEASE]

<TABLE>
<CAPTION>

     1.4  "BASE RENT":                                                                                    Annually Per
                                                                                                          Rentable
                                  Period                                Monthly                           Square Foot
                                  ------                                -------                           ------------
<S>                               <C>                                   <C>                                <C>
                                  First Lease Year                          $290,599.54**                   $26.45
                                  Second Lease Year                         $299,828.41                     $27.29
                                  Third Lease Year                          $309,386.88                     $28.16
                                  Fourth Lease Year                         $319,165.09                     $29.05
                                  Fifth Lease Year                          $329,163.03                     $29.96
                                  Sixth Lease Year                          $339,600.44                     $30.91
                                  Seventh Lease Year                        $350,257.59                     $31.88
                                  Eighth Lease Year                         $361,354.21                     $32.89
                                  Ninth Lease Year                          $372,670.56                     $33.92
                                  Tenth Lease Year                          $384,316.52                     $34.98
                                  **[SEE SECTION 4 OF LEASE]

     1.5  OPERATING EXPENSES:     Base Year: 2001
                                  Pro Rata Share: 69.499%

     1.6  "DEPOSIT":              None but see Addendum re Letter of Credit

</TABLE>
<PAGE>

     1.7  "PERMITTED USE":             Primary Use as General Business Offices,
                                       and Ancillary Uses in accordance with
                                       Section 10.1

     1.8  "GUARANTOR":                 None

     1.9  PARKING :                    460 surface spaces
                                       20 garage spaces
                                       [based on a total of 4 per 1,000 usable]
                                                                        ------

     1.10 LANDLORD'S NOTICE ADDRESS :  DTC ASSOCIATES, LLC, c/o Miller Global
                                       Properties, LLC, 4643 S.  Ulster Street,
                                       Suite 1500, Denver, CO 80237, Attn:
                                       Donald E. Spiegleman, Esq. or Mr. Paul
                                       Hogan

     with a copy to Building Manager:  [name, address and phone numbers
                                       to be provided by Landlord]
                                       _________________________________
                                       Facsimile: ______________________
                                       Telephone: ______________________

     1.11 RENT PAYMENT ADDRESS :       DTC ASSOCIATES, LLC, c/o Miller Global
                                       Properties, LLC, 4643 S. Ulster Street,
                                       Suite 1500, Denver, CO 80237

     1.12 LANDLORD'S TAX I.D. :        84-1474242
                                       ----------

     1.13 TENANT'S NOTICE ADDRESS :
          Precommencement Address:     1110 Herndon Parkway
                                       Suite 300
                                       Herndon, Virginia 20170
                                       Attention: Mr. David N. Mahoney, COO

          Post Commencement Address:   13530 Dulles Technology Drive, Suite 500
                                       Herndon, Virginia

           With a copy to:             Shaw Pittman
                                       Attention:  Craig Chason, Esq.
                                       1676 International Drive
                                       McLean, Virginia 22102-4835

     1.14 TENANT'S TAX I.D. :          52-1990403
                                       ----------

     1.15 LANDLORD'S BROKER :          CB Richard Ellis, Inc.

     1.16 COOPERATING BROKER :         CB Richard Ellis, Inc.

     1.17 ATTACHMENTS :                [check if applicable]
                                        x    Addendum
                                       ---
                                        x    Exhibit A - The Premises
                                       ---
                                        x    Exhibit B - Real Property
                                       ---
                                        x    Exhibit C - Operating Expenses
                                       ---

                                       2
<PAGE>

                                        x    Exhibit D - Commencement
                                       ---   Certificate
                                        x    Exhibit E - Rules and Regulations
                                       ---
                                        x    Exhibit F - SNDA
                                       ---
                                        x    Exhibit G - Letter of Credit
                                       ---
                                        x    Exhibit H - Building Signage
                                       ---
                                        x    Exhibit I -  Janitorial
                                       ---   Specifications
                                        x    Exhibit J -  Work Letter
                                       ---

  2. GENERAL COVENANTS.  Tenant leases the Premises from Landlord for the
     -----------------
term and upon the terms herein.  Tenant covenants and agrees to pay Rent and
perform the obligations hereafter set forth and in consideration therefor
Landlord leases to Tenant the Premises as depicted on the plat attached as
Exhibit A, together with a non-exclusive right, subject to the provisions
hereof, to use plazas, common areas (including the Building's loading docks,
doors, platforms, staging areas and swing passenger/freight elevator), or other
areas on the real property legally described on Exhibit B (the "Real Property")
designated by Landlord for the exclusive or non-exclusive use of the tenants of
the Building ("Common Areas").  The Building, Real Property, Common Areas, and
appurtenances are hereinafter collectively sometimes called the "Building
Complex."  The lease of the Premises also is subject to any covenants,
conditions and restrictions of record as of the date hereof and hereafter
recorded with the consent of Tenant.  Prior to the date hereof, Landlord has
delivered to Tenant a copy of Landlord's current title policy.

  3. TERM.  The Initial Term of the Lease commences at 12:01 a.m. on the
     ----
Commencement Date as determined pursuant to and in accordance with the Work
Letter and terminates at 12:00 midnight on the last day (the "Expiration Date")
of the tenth Lease Year.  The Initial Term together with any extensions thereof
is herein referred to as the "Term".  The Initial Term shall be subject to
adjustment in accordance with Section 5.1.  "Lease Year" means a period of one
year commencing on the first day of the month in which the Phase II Completion
Date (as determined in accordance with the Work Letter) occurs and each
successive one-year period, except that if the Phase II Completion Date is not
the first day of the month, then the first Lease Year shall commence on the
Phase II Completion Date and shall continue for the balance of the month in
which the Phase II Completion Date occurs and for a period ending on the last
day of the 12th full calendar month after the Phase II Completion Date, and each
Lease Year after the first Lease Year shall be the 12 full calendar months
thereafter.

  4. RENT.  Subject to the provisions below, commencing on the Commencement
     ----
Date and on the first day of each month thereafter, Tenant shall pay Base Rent
in the amount stated in Section 1.4, in advance without notice (all amounts,
including Base Rent, to be paid by Tenant pursuant to this Lease as the context
requires are sometimes referred to collectively as "Rent(s)").  Rents shall be
paid without set off, abatement, or diminution except as otherwise expressly set
forth herein, at the address set forth in Section 1.11 above, or at such other
place as Landlord from time to time designates in writing.  Notwithstanding
anything to the contrary set forth in Section 1.4 above, Tenant  shall only be
obligated to pay Base Rent attributable to Phase I ($145,031.96 per month,
calculated on the basis of prorating the Base Rent provided in Section 1.4)
during the period beginning with the Commencement Date as determined pursuant to
the Work Letter until the Phase II Completion Date as provided in Section 5.1;
Tenant shall have no obligation to pay Base Rent attributable to Phase II during
such period.  If the Commencement Date is not the first day of a month, then on
the Commencement Date Tenant shall pay the Base Rent with respect to Phase I for
the month in which the Commencement Date occurs, calculated on a per diem basis
(based on the number of days in the relevant month) of the monthly installment
of the Base Rent payable during the first month of the Term of the Lease. If the
Phase II Completion Date is not the first day of a month, then on the Phase II
Completion Date Tenant shall pay the Base Rent with respect to Phase II for the
month in which the Phase II Completion Date occurs, calculated on a per diem
basis (based on the number of days in such month) of the monthly installment of
the Base Rent payable during such month.

                                       3
<PAGE>

  5. COMPLETION OR REMODELING OF THE PREMISES.
     ----------------------------------------

     5.1  Provisions regarding remodeling or tenant finish work (the "Tenant
Work") in the Premises, if any, are set forth in a work letter attached to this
Lease (the "Work Letter"). "Initial Tenant Finish" means the Premises in its
as-is condition as modified by all work, if any, performed by Landlord at its
expense prior to the Commencement Date in accordance with the Work Letter.
Except as provided in the Work Letter, Landlord has no obligation for the
completion or remodeling of the Premises, and Tenant accepts the Premises in its
"as is" condition upon delivery by Landlord in accordance with the Work Letter
(subject to punchlist items and latent defects, such items and defects to be
resolved pursuant to the Work Letter). If Landlord is delayed in delivering
Phase I of the Premises to Tenant in accordance with the Work Letter, then the
Commencement Date will be postponed to the date Landlord delivers Phase I to
Tenant. If delivery is on other than the first day of the month, then the
Commencement Date (for purposes of triggering the running of the Initial Term of
10 years and 4 months) will be the first day of the month following the delivery
date for Phase I but all provisions hereof, including Tenant's obligation to pay
Rent (prorated for a partial month), will be in effect as of the delivery date.
The postponement of Tenant's obligation to pay Rent is in full settlement of all
claims which Tenant may otherwise have by reason of such delay. If the Phase II
Completion Date is delayed beyond January 1, 2001, the Expiration Date shall be
extended so that the Initial Term expires at the end of the month 10 years
following the Phase II Completion Date. As soon as the Phase II Completion Date
occurs, Landlord and Tenant agree to execute a commencement agreement in the
form attached as Exhibit D setting forth the exact Commencement Date and
Expiration Date. Notwithstanding the foregoing or the Work Letter, if the
Commencement Date has not occurred by March 15, 2001 (the "Outside Date"), as
such date shall be extended on a day-for-day basis due to "Tenant Delay" as
defined in the Work Letter, or causes beyond Landlord's reasonable control (up
to a maximum of 30 days), Tenant, at its sole option, may terminate this Lease
upon notice to Landlord given no later than 10 days after the Outside Date. If
Tenant exercises its right to terminate hereunder, effective on the day such
notice is received by Landlord, this Lease will be null and void and of no
further force and effect. If Tenant fails to timely exercise its right to
terminate, this Lease will continue in full force and effect and the
Commencement Date will be established in accordance with the Work Letter.

  5.2  Except as provided in the Work Letter, taking possession of the
Premises by Tenant is conclusive evidence that the Premises are in the condition
agreed between Landlord and Tenant and acknowledgment by Tenant of satisfactory
completion of any work which Landlord has agreed to perform, subject to the
punchlist and latent defects provisions of the Work Letter.

  6. OPERATING EXPENSES. Tenant shall pay additional Rent in accordance with
     ------------------
Exhibit C attached hereto.

                                       4
<PAGE>

  7. SERVICES.
     --------

     7.1  Landlord shall manage, operate, maintain, and repair the Building in
accordance with standards customarily provided in first-class office buildings
in the Herndon-Dulles metropolitan area.  Subject to the provisions below,
Landlord agrees, without charge, in accordance with standards reasonably
determined by Landlord from time to time for the Building (which standards shall
provide for services comparable to services provided by office buildings of
similar size and quality in the Herndon-Dulles metropolitan area):  (1) to
furnish hot and cold running water at those points of supply for general use of
tenants of the Building (including for the separate men's and women's showers
provided in Landlord's Drawings as part of the ground floor restrooms) on a 24-
hours-a-day, seven-days-a-week basis; (2) to furnish to interior Common Areas
heated or cooled air (as applicable), electrical current on a 24-hours-a-day,
seven-days-a-week basis for lighting and safety purposes, janitorial services,
and maintenance; (3) during Ordinary Business Hours to furnish heated or cooled
air to the Premises for standard office use consistent with the design capacity
of the Building HVAC system in accordance with Building Improvements as
described in the Work Letter attached hereto as Exhibit J; (4) to furnish,
subject to availability and capacity of building systems in accordance with the
Building Improvements, unfiltered treated chilled water for use in Tenant's
packaged HVAC systems provided that such systems are approved by Landlord,
including strainers, pumping systems and controls (it being agreed that Tenant
may install supplemental HVAC units within the Premises consistent with its
design plans for the Tenant Work); (5) to provide, during Ordinary Business
Hours, the general use of passenger elevators for ingress and egress to and from
the Premises (at least one such elevator shall be available at all times except
in the case of emergencies or repair) and a card-key access control system for
the Building that will afford Tenant access to the Building on a 24-hours per
day, 7-days per week basis, subject to required repairs and maintenance or other
uncontrollable interruptions;  (6) to provide janitorial services for the
Premises to the extent of the Initial Tenant Finish (including window washing of
the outside of exterior windows) after Ordinary Business Hours in accordance
with the specifications attached hereto as Exhibit I; and (7) on a 24-hours-a-
day, seven-days-a-week basis, to cause electric current to be supplied to the
Premises in accordance with the Building Improvements and hot and cold water
(items (1) through (7) are collectively called "Services"). "Ordinary Business
Hours" means 8:00 a.m. to 7:00 p.m. Monday through Friday and 9:00 a.m. to 2:00
p.m. on Saturdays, Legal Holidays excepted.  "Legal Holidays" mean New Year's
Day, Martin Luther King Day, Inauguration Day, Presidents' Day, Memorial Day,
Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day,
Christmas Day, and such other national holidays hereafter established by the
United States Government that are recognized by similar first class office
buildings in the Herndon-Dulles metropolitan area.  Any security system or other
security measures (collectively "Security") that Landlord may undertake are for
protection of the physical structures only and shall not be relied upon by
Tenant, its agents, employees, contractors or invitees, including subtenants or
assignees (collectively, "Invitees") to protect their person, or property,
including Tenant's Property.  Tenant shall not knowingly do anything to
circumvent or allow others to circumvent security.  Landlord shall not be liable
for any failure of any security to operate or for any breach or circumvention of
the security by others, and Landlord makes no representations or warranties
concerning the installation, performance and monitoring of the security or that
it will detect or avert occurrences which any such security is intended or
expected to detect or avert.  Landlord shall, at its cost, provide an initial
set of security access cards to the Building in an amount up to 527 Building
access cards.  Tenant shall have a right to install its own security system (the
"Tenant's System") in the Premises provided that such system is installed in
such a manner as to permit the continued operation of Landlord's security and
life safety systems.  Tenant shall provide Landlord with keys, access cards or
access numbers for any security system installed by Tenant to permit Landlord to
have access to the Premises, provided that such access is in accordance with
Section 11.2 of this Lease.  Subject to Section 12.3 of this Lease, if Tenant
does not elect to remove Tenant's System on or prior to the expiration or
earlier termination of the Lease, Tenant shall deliver to Landlord all manuals
and other equipment required for operation of the Tenant's System and leave in
place all cabling and related equipment installed in the Premises.

     7.2  The electricity for the lighting, equipment and machinery in the
Premises shall be separately metered by a submeter or checkmeter (the cost of
installing and maintaining the meter shall be paid by Tenant); Tenant shall not
separately contract with the utility provider, but shall be billed by Landlord
based on the submeter or checkmeter and the actual costs paid by Landlord for
such electrical service, without markup and such amounts shall be in addition to
(and not duplicative of) any amounts required to be paid by Tenant as Operating
Expenses under the foregoing provisions or as charges for Excess Usage, as
hereinafter provided.  In the event that all or any portion of such electricity
is not separately metered, Landlord shall make a reasonable determination of
Tenant's proportionate share of the cost of such utility and Tenant shall pay
such amount upon billing by Landlord. All amounts to be paid Landlord hereunder
shall be deemed Rents.  In addition, Tenant shall be responsible for and shall
pay promptly, directly to the appropriate supplier, all charges for telephone,
interior landscape maintenance, and other materials and services furnished
directly to Tenant or the Premises, or used by Tenant in or about the Premises
during the Term, together with any taxes thereon.  Electricity shall be provided
to the Premises 24 hours a day without notice being required and without
additional charges for after-hours usage of such facilities.  Tenant shall also
pay the cost of replacing light bulbs and/or tubes and ballast used in all
lighting in the Premises other than that provided by Landlord to all tenants of
the Building.   It is agreed that if Tenant requires HVAC services beyond
Ordinary Business Hours, Landlord will

                                       5
<PAGE>

furnish such HVAC services, provided Tenant gives Landlord's agent sufficient
advance notice of such requirement and Tenant pays for the cost of such extra
service in accordance with Landlord's then current schedule of costs and
assessments for such extra service. As of the date hereof, Landlord has
estimated that the per hour charge for air-conditioning outside Ordinary
Business Hours will be $35.00 per floor served (all or any portion); such charge
is subject to increase based on increases in costs of utilities included in such
costs and only after prior notice to Tenant. Sufficient notice for purposes of
the preceding sentence shall be deemed to include 1 hour notice if given between
the hours of 8:00 a.m. and 5:00 p.m. Monday - Friday, 1 hour notice if given
between the hours of 8:00 a.m. and noon on Saturday, and if such extra service
is required on Sundays or holidays then sufficient notice shall be given if
given on the day immediately preceding the Sunday or holiday within the notice
hours specified above for such day. Any electricity to be supplied to a
segregated computer room, including electricity for the separate self-contained
HVAC units servicing such area, if any, shall be included in the separate
metering of electricity for the Premises referred to above; Tenant shall pay the
cost of installing and maintaining any such separate self-contained HVAC units.

     7.3  If Tenant requires janitorial services other than those included as
standard Services, Tenant shall separately pay for the direct, out-of-pocket,
third party costs of such services monthly within 30 days following receipt of
written billings by Landlord, or in any event (i.e., regardless if Tenant
requires other than standard Services), Tenant may, at Tenant's option,
separately contract for such services with the same company used by Landlord to
furnish janitorial services to the Building or another janitorial service
provider selected by Tenant and subject to Landlord's reasonable approval.

     7.4  Upon prior notice to Tenant (except in the event of an emergency),
Landlord may temporarily discontinue, reduce, or curtail Services when necessary
due to accident, repairs, alterations, strikes, lockouts, Applicable Laws (as
defined in Section 10 below), or any other happening beyond Landlord's
reasonable control.  Landlord is not liable for damages to Tenant or any other
party as a result of any interruption, reduction, or discontinuance of Services
(either temporary or permanent) nor shall the occurrence of any such event be
construed as an eviction of Tenant, cause or permit an abatement, reduction or
setoff of Rent, or operate to release Tenant from Tenant's obligations.
Notwithstanding the foregoing to the contrary, if (a) any interruption of the
Services described in Section 7.1 above resulting from Landlord's (or its
employee's agent's or contractor's) negligence or willful misconduct shall
continue for more than 4 consecutive business days, or (b) if any interruption
of Services not resulting from Landlord's (or its agent's or employee's)
negligence or willful misconduct nor from Tenant's (or its agents or employees)
negligence or willful misconduct shall continue for more than 8 consecutive
business days, and in either of the foregoing instances if (i) such interruption
is not the result of any willful misconduct or negligent act or breach of
obligations or omission of Tenant or Tenant's employees, contractors, or agents,
or any persons occupying the Premises under Tenant, and (ii) such interruption
renders more than 25% of the Premises untenantable or inaccessible by Tenant,
then, as Tenant's sole and exclusive remedy therefor, all Base Rent and
Additional Rent payable hereunder with respect to such portion of the Premises
shall be abated for the period beginning as of the first day of such
interruption and continuing until full use of the Premises is restored to
Tenant.  Landlord will use its commercially reasonable efforts to cause the
restoration of any interrupted Services; further, should any equipment or
machinery in the Building break down so as to render the Premises unusable by
Tenant, Landlord shall promptly repair or replace it (subject to delays which
result from strikes, unavailability of parts or other materials, or other
matters beyond Landlord's reasonable control).

     7.5  Tenant shall promptly notify Landlord of any accidents or defects in
the Building of which Tenant becomes aware, including defects in pipes, electric
wiring, and HVAC equipment, and of any condition which may cause injury or
damage to the Building or any person or property therein, but any failure on the
part of Tenant to so notify Landlord shall not abrogate Landlord's maintenance
and repair obligations hereunder.

     7.6  Landlord agrees to competitively bid all contracts for service and
materials (including the property management contract) for the operation of the
Building to at least 3 service providers.  Any selection made by Landlord shall
be made from among the 3 who provided bids for each particular service, in the
exercise of Landlord's commercially reasonable judgment.

  8. QUIET ENJOYMENT.  So long as an Event of Default has not occurred, Tenant
     ---------------
is entitled to the quiet enjoyment and peaceful possession of the Premises
subject to the provisions of this Lease.   Landlord shall under no circumstances
be held responsible for restriction or disruption of access to the Building from
public streets caused by construction work or other actions taken by or on
behalf of governmental authorities, or for actions taken by other tenants (their
employees, agents, visitors, contractors or invitees), or any other cause not
entirely within Landlord's direct control, and same shall not constitute a
constructive eviction of Tenant nor give rise to any right or remedy of Tenant
against Landlord of any nature or kind; provided, however, that with respect to
construction work or other actions taken by other tenants, Landlord shall use
reasonable efforts to ensure that Tenant's access to, and use of, the Premises
is not materially adversely affected.  This covenant of quiet enjoyment is in
lieu of any covenant of quiet enjoyment provided or implied by law, and Tenant
expressly waives any such other covenant of quiet enjoyment to the extent
broader than the covenant contained in this Section.

                                       6
<PAGE>

  9.  DEPOSIT. [INTENTIONALLY DELETED]
      -------

  10. CHARACTER OF OCCUPANCY.
      ----------------------

      10.1 Tenant shall occupy the Premises for the Permitted Use and for no
other purpose, and use it in a careful, safe, and proper manner.  The term
"Permitted Use" shall mean: general business office use (the "Primary Use")
and for activities ancillary thereto (the "Ancillary Uses") provided that
Ancillary Uses shall not be the primary use of the Premises, are permitted by
Applicable Laws (as hereinafter defined), and are expressly approved by
Landlord, which approval shall not be unreasonably withheld if such uses are
consistent with first class suburban general office building uses and so long as
in keeping with Building's first-class quality and allowed under zoning
applicable to the Building.  Tenant shall be responsible for obtaining any
approvals or permits required for the Ancillary Uses under Applicable Laws and
the declaration of protective covenants applicable to the Real Property (the
"Declaration").  Subject to Landlord's obligations under Sections 10 and 11
hereof, Tenant, at Tenant's expense, shall comply with the Declaration and all
applicable federal, state, city, quasi-governmental and utility provider laws,
codes, rules, and regulations now or hereafter in effect ("Applicable Laws")
which impose any duty upon Landlord or Tenant with respect to the occupation or
alteration of the Premises. Tenant shall not commit or permit waste or any
nuisance on or in the Premises.  Tenant agrees not to store, keep, use, sell,
dispose of or offer for sale in, upon or from the Premises any article or
substance prohibited by any insurance policy covering the Building Complex nor
shall Tenant keep, store, produce or dispose of on, in or from the Premises or
the Building Complex any Hazardous Materials, except customary office and
cleaning supplies customarily associated with the Permitted Use of the Premises
that are disclosed to Landlord and are stored and used in accordance with
Applicable Laws and applicable industry standards.  At the expiration or earlier
termination of this Lease, Tenant shall surrender the Premises to Landlord free
of Hazardous Materials (except to the extent that any such Hazardous Materials
were brought into the Premises by Landlord, its employees, contractors, or
agents) and in compliance with all Environmental Laws (except to the extent any
such non-compliance was caused by Landlord or its agents, employees or
contractors).   As used in this Lease, "Hazardous Materials" means (a) asbestos
and any asbestos containing material and any substance that is then defined or
listed in, or otherwise classified pursuant to, any Environmental Law or any
other applicable Law as a "hazardous substance," "hazardous material,"
"hazardous waste," "infectious waste," "toxic substance," "toxic pollutant" or
any other formulation intended to define, list, or classify substances by reason
of deleterious properties such as ignitability, corrosivity, reactivity,
carcinogenicity, toxicity, reproductive toxicity, or Toxicity Characteristic
Leaching Procedure (TCLP) toxicity, (b) any petroleum and drilling fluids,
produced waters, and other wastes associated with the exploration, development
or production of crude oil, natural gas, or geothermal resources, and  (c) any
petroleum product, polychlorinated biphenyls, urea formaldehyde, radon gas,
radioactive material (including any source, special nuclear, or byproduct
material), medical waste, chlorofluorocarbon, lead or lead-based product, and
(d) any other substance whose presence could be detrimental to the Buildings,
Land or Complex or hazardous to health or the environment. "Environmental Law"
means any present and future law and any amendments (whether common law,
statute, rule, order, regulation or otherwise), permits and other requirements
or guidelines of governmental authorities applicable to the Buildings, Land, or
Complex and relating to the environment and environmental conditions or to any
Hazardous Material (including, without limitation, CERCLA, 42 U.S.C. (S) 9601 et
seq., the Resource Conservation and Recovery Act of 1976, 42 U.S.C. (S) 6901 et
seq., the Hazardous Materials Transportation Act, 49 U.S.C. (S) 1801 et seq.,
the Federal Water Pollution Control Act, 33 U.S.C. (S) 1251 et seq., the Clean
Air Act, 33 U.S.C. (S) 7401 et seq., the Toxic Substances Control Act, 15 U.S.C.
(S) 2601 et seq., the Safe Drinking Water Act, 42 U.S.C. (S) 300f et seq., the
Emergency Planning and Community Right-To-Know Act, 42 U.S.C. (S) 1101 et seq.,
the Occupational Safety and Health Act, 29 U.S.C. (S) 651 et seq., and any so-
called "Super Fund" or "Super Lien" law, any Law requiring the filing of
reports and notices relating to hazardous substances, environmental laws
administered by the Environmental Protection Agency, and any similar state and
local laws, all amendments thereto and all regulations, orders, decisions, and
decrees now or hereafter promulgated thereunder concerning the environment,
industrial hygiene or public health or safety).

      10.2 In the event Landlord is advised, or it shall come to Landlord's
attention, that Hazardous Materials exist in the Premises in violation of any
Environmental Laws that were not introduced therein by Tenant or Tenant's
Invitees, Landlord shall take all commercially reasonable steps necessary to
promptly remove or remediate (or cause to be removed or remediated) all such
Hazardous Materials, and in doing so, Landlord shall use its reasonable efforts
not to interfere with the conduct of Tenant's business.

      10.3 Notwithstanding anything to the contrary contained in this Lease, it
is agreed that Landlord shall be responsible for compliance with any present or
future Applicable Laws with respect to (a) those elements and components of the
Base Building Systems and structure that are situated outside the perimeter of
the Premises or are within vertical penetrations running through the Premises,
and (b) the common areas of the Buildings, unless such Applicable Laws are
imposed because of Tenant's particular use of the Premises (as opposed to office
use generally) or any improvements constructed by Tenant in the Premises or to
accommodate special needs of specific employees of Tenant.  Notwithstanding
anything to the contrary in this Lease, all additions, replacements or
alterations to the

                                       7
<PAGE>

Building and Building Improvements (including those portions located within the
Premises) that are required due to the enactment of any future Applicable Laws
shall be performed by Landlord.

  11.  MAINTENANCE, ALTERATIONS AND REENTRY BY LANDLORD.
       ------------------------------------------------

       11.1 Landlord shall keep, maintain, repair and replace as appropriate,
the foundation, roof, exterior walls, structural portions (including columns
within the Premises and the vertical sprinkler riser through the Buildings), and
exterior glass and windows of the Buildings (specifically excluding the interior
walls, doors, partitions, locks, and door jambs in the Premises), as well as all
building standard mechanical, plumbing, heating, air conditioning, sprinkler and
electrical systems and utility service lines therein (exclusive of telephone,
telecommunications or data lines), the plumbing system to and from the Premises
and core area restrooms within the Premises, and the driveways, parking areas
and grounds adjacent to the Buildings in good condition and repair, and the
costs incurred by Landlord in maintaining and repairing such items shall be
included in the Operating Expenses of the Buildings. All common or public areas
of the Buildings, land, and Building Complex shall be maintained by Landlord in
accordance with standards customarily maintained for comparable office buildings
of a similar class in the Herndon-Dulles metropolitan area. Tenant shall
promptly provide Landlord with notice of any defect or need for repairs in or
about the Building of which Tenant is aware; provided, however, Landlord's
obligation to repair hereunder shall not be limited to matters of which it has
been given notice by Tenant. Notwithstanding any of the foregoing to the
contrary: (a) maintenance and repair of special tenant areas, facilities,
finishes and equipment (including, but not limited to, any special fire
protection equipment, telecommunications and computer equipment, kitchen/galley
equipment, air-conditioning equipment serving the Premises only and all other
furniture, furnishings and equipment of Tenant and all Alterations) shall be the
sole responsibility of Tenant and shall be deemed not to be a part of the
Buildings' structure and systems; and (b) Landlord shall have no obligation to
make any repairs (i) within the Premises brought about by any willful misconduct
or negligence of Tenant or any Invitee, or (ii) to the Buildings brought about
by any willful misconduct or negligence of Tenant or its employees, contractors,
agents, subtenants, or assignees. If Landlord fails or is unable to comply with
its obligations under this Section 11.1 or Section 10.2 above, and if all or at
least twenty-five percent (25%) of the Premises is thereby rendered unusable by
Tenant for a continuous period of five (5) consecutive business days after
Tenant gives Landlord notice thereof as a result of a failure or inability of
Landlord to comply with Landlord's obligations under this Section 11.1 or
Section 10.2 above, then, so long as no Event of Default exists under this Lease
and provided such failure or inability was not caused by the negligence or
willful misconduct of Tenant or its Invitees, Tenant shall be entitled to an
abatement of the Base Rent payable hereunder with respect to the portion of the
Premises that is unusable for the period beginning on the day after such five
(5) business day period ends (or any such earlier date to the extent Landlord
receives rent loss insurance proceeds therefor) and continuing until the use of
the Premises is restored to Tenant.

       11.2 Landlord or Landlord's agents may at any time enter the Premises
after reasonable prior notice to Tenant (except in an emergency and during
regularly scheduled janitorial or cleaning, repairs or maintenance, when no
notice is required) for examination and inspection, or to perform, if Landlord
elects and only if Tenant has been given no less than ten (10) days prior notice
(except in an emergency, when no notice is required) and an opportunity to
perform for itself, any obligations of Tenant which Tenant fails to perform or
such cleaning, maintenance, janitorial services, repairs, replacements,
additions, or alterations as Landlord deems reasonably necessary for the safety,
improvement, or preservation of the Premises or other portions of the Building
Complex or as required by Applicable Laws. Upon reasonable prior notice,
Landlord or Landlord's agents may also show the Premises to prospective
purchasers and Mortgagees at any time and to prospective tenants during the last
12 months of the Term. In connection with any above-mentioned entry, Landlord
shall endeavor to minimize the disruption to Tenant's use of the Premises. Any
such reentry does not constitute an eviction or entitle Tenant to abatement of
Rent. Notwithstanding anything to the contrary set forth in this Lease, except
in the event of an emergency, Landlord shall not be permitted access to limited
portions of the Premises previously designated by notice from Tenant to Landlord
as security areas, unless Landlord or its representatives are accompanied by an
agent of Tenant designated and made available by Tenant for such purpose;
Landlord shall have a right in the event of a casualty or other life-threatening
emergency and if an agent of Tenant is unavailable to escort Landlord or
Landlord's representative into the security area, to break down the doors to
such secured areas for the purpose of dealing with the emergency and Tenant
shall be responsible for any damage caused by such entrance. Landlord shall have
no obligation to provide janitorial services to such secured areas unless
expressly requested by Tenant and Tenant pays for any added janitorial costs
arising from Tenant's security arrangements (it being agreed that if the
security area is substantially similar in functionality and layout to non-
security areas of the Premises and if Tenant provides access during normal
janitorial hours, then there shall be no such additional janitorial costs).
Landlord may make such alterations or changes in other portions of the Building
Complex as Landlord desires so long as such alterations and changes do not
unreasonably interfere with Tenant's use and occupancy of, or access to, the
Premises or materially increase Tenant's obligations and subject to the
following provisions: (i) unless required by Applicable Laws, if Landlord
changes the street address, then Landlord shall pay Tenant's reasonable costs of
replacing a reasonable stock of its stationery that references the old address
and (ii) if Landlord erects or changes pipes and conduits in and through the
Premises such alterations and changes shall not materially interfere with
Tenant's use or occupancy of, or access to, the Premises and shall be installed
behind the

                                       8
<PAGE>

walls, under the floors, or above the ceilings. Landlord may use the Common
Areas and one or more street entrances to the Building Complex as may be
necessary in Landlord's judgment to complete such work in accordance with
Section 27.12.

       11.3 If any damage (other than normal wear and tear) to the permanent
improvements in Premises (exclusive of Tenant's personal property or Tenant's
trade fixtures) is caused by the negligence or willful misconduct of Landlord or
Landlord's employees, agents or contractors, Landlord shall, at its sole
expense, repair promptly such damage or cause such damage to be repaired
promptly.

  12.  ALTERATIONS AND REPAIRS BY TENANT.
       ---------------------------------

       12.1 After completion of the Tenant Work, Tenant shall not make any
alterations to the Premises during the Term, including installation of equipment
or machinery which requires modifications to existing electrical outlets or
increases Tenant's usage of electricity beyond the capacity of the Building
systems (collectively "Alterations") without in each instance first obtaining
the written consent of Landlord, which consent shall not be unreasonably
withheld, conditioned or delayed.  Landlord's consent or approval of the plans,
specifications and working drawings for any Alterations shall not constitute any
warranty or representation by Landlord (and shall not impose any liability on
Landlord) as to their completeness, design sufficiency, or compliance with
Applicable Laws; provided, however, Tenant may, without Landlord's consent (but
with notice of the nature of the changes, as reflected in record or as-built
drawings promptly delivered to Landlord following completion of Alterations)
perform interior non-structural Alterations not involving modifications to the
Base Building plumbing, electrical, mechanical or life safety systems (as
distinguished from the portions of such systems located within the Premises that
are installed by Tenant as Initial Tenant Finish, if any) provided the cost of
any particular Alterations  (taking into account together all Alterations being
made as part of a common or phased plan) does not exceed One Hundred Twenty Five
Thousand Dollars ($125,000).  Tenant shall at its cost: pay all reasonable third
party engineering costs incurred by Landlord as to all Alterations for which
Landlord's consent is required, obtain all governmental permits and approvals
required (except if the Tenant Work or Alterations are performed by Landlord, in
which event Landlord shall obtain the necessary governmental permits and
approvals), cause all Alterations to be completed in compliance with Applicable
Laws and reasonable requirements of Landlord's insurance, and provide Landlord
with record or as-built drawings promptly following completion of Alterations.
All such work relating to Alterations shall be performed in a good and
workmanlike manner, using new or like-new materials and equipment at least equal
in quality to the Initial Tenant Finish. All Alterations, repair and
maintenance work performed by Tenant shall be done at Tenant's expense using
contractors licensed to perform the applicable work in the Commonwealth of
Virginia who are reasonably approved by Landlord, which contractors shall
complete the Alterations in accordance with Landlord's reasonable contractor
rules attached as Exhibit 2 to the Work Letter. If such work is not performed
by Landlord's employees and such work is performed subsequent to the Tenant Work
contemplated in the Work Letter, involves the Building systems and/or structural
portions of the Building and Landlord reasonably determines that supervision of
such work is required, Tenant shall pay Landlord, upon receipt of an invoice, a
supervisory fee based on actual costs paid to third parties. If Landlord
authorizes such persons to perform work, Tenant shall deliver to Landlord prior
to commencement of work, certificates issued by insurance companies qualified to
do business in the state in which the Premises are located, evidencing that
worker's compensation, public liability insurance, and property damage insurance
(in amounts, with companies and on forms satisfactory to Landlord) are in force
and maintained by all contractors and subcontractors engaged to perform such
work. All liability policies shall name Landlord, Building Manager, and
Mortgagee as additional insureds. Each certificate shall provide that the
insurance may not be cancelled or modified without 10 days' prior notice to
Landlord and Mortgagee. Landlord also has the right to post notices in the
Premises in locations designated by Landlord stating that Landlord is not
responsible for payment for such work and containing such other information as
Landlord deems necessary. All such work shall be performed in a manner which
does not unreasonably interfere with Landlord or other tenants of the Building,
or impose additional expense upon Landlord in the operation of the Building
Complex.

       12.2 Tenant shall keep the Premises in as good order, condition, and
repair and in an orderly state, as on the Commencement Date, loss by fire or
other casualty or ordinary wear excepted, and damage due to the negligence or
willful misconduct of Landlord or Landlord's agents, contractors, or employees.
The liability of Tenant for the costs and expenses of repairs shall be reduced
by the amount of any insurance proceeds for which Landlord is entitled (or for
which Landlord would have been entitled had Landlord obtained and maintained the
insurance required pursuant to the terms of this Lease).

       12.3 All Alterations, including partitions, paneling, carpeting, drapes
or other window coverings, and light fixtures (but not including movable office
furniture not attached to the Building), are deemed a part of the real estate
and the property of Landlord and remain upon and be surrendered with the
Premises at the end of the Term, whether by lapse of time or otherwise, unless
(a) Tenant requests, when it submits its plans and specifications for such
Alteration to Landlord for Landlord's approval, Landlord's consent to Tenant's
removal of such Alterations upon the expiration or earlier termination of the
Lease Term and Landlord so consents, or (b) Landlord specifies in its approval
of the plans and specifications for such Alterations that Tenant must remove the
Alterations upon the expiration or

                                       9
<PAGE>

earlier termination of the Term of the Lease, except that if Tenant is not in
default under this Lease beyond any applicable notice and cure period, then
Tenant shall have the right to remove, prior to the expiration or earlier
termination of the Term of the Lease, movable furniture, Tenant's System
(excluding mechanical door locks), movable furnishings and movable trade
fixtures installed in the Premises by Tenant solely at Tenant's expense;
provided, however, that Landlord may only require that an Alteration be removed
upon the expiration or earlier termination of the Term of the Lease if in
Landlord's reasonably professional judgment such Alteration would, as a result
of the unique nature of such items or the anticipated difficulty or expense
required to remove such items, expose Landlord to greater expense and effort in
order to remove such items than the standard demolition of such space would have
otherwise involved. If Tenant is required to remove all or part of any
Alterations, Tenant shall at Tenant's expense promptly remove the Alterations
specified and restore the Premises to its prior condition, reasonable wear and
tear and damage due to casualty excepted. In lieu of requiring Tenant to restore
or alter the ceiling of the Premises upon expiration or earlier termination of
the Lease, Landlord and Tenant have agreed on compensation to Landlord in the
form of a Ceiling Reimbursement fee as described in greater detail in the Letter
of Credit provision of the Addendum.

  13.  CONSTRUCTION LIENS.  Tenant shall pay for all work done on the Premises
       ------------------
by Tenant or at its request (other than the Initial Tenant Finish) of a
character which may result in liens on Landlord's or Tenant's interest and
Tenant will keep the Premises free of all construction liens, and other liens on
account of such work.  Tenant indemnifies, defends, and saves Landlord and all
Mortgagees harmless from all liability, loss, damage, or expenses, including
attorneys' fees, on account of any claims of laborers, materialmen or others for
work performed or for materials or supplies furnished to Tenant or persons
claiming under Tenant.  If any lien is recorded against the Premises or Building
or any suit affecting title thereto is commenced as a result of such work, or
supplying of materials, Tenant shall cause such lien to be removed of record
within 10 days after notice from Landlord.  If Tenant desires to contest any
claim, Tenant must furnish Landlord adequate security or a bond of at least 150%
of the amount of the claim, plus estimated reasonable costs and, if a final
judgment establishing the validity of any lien is entered, Tenant shall
immediately pay and satisfy the same.  If Tenant fails to proceed as aforesaid,
Landlord may pay such amount and any costs, and the amount paid, together with
reasonable attorneys' fees incurred, shall be due to Landlord within 10 days
following notice therefor.

  14.  SUBLETTING AND ASSIGNMENT.
       -------------------------

       14.1 Tenant shall not sublet any part of the Premises nor assign or
otherwise transfer this Lease or any interest herein (sometimes referred to as
"Transfer," and the subtenant or assignee may be referred to as "Transferee")
without the consent of Landlord first being obtained, which consent will not be
unreasonably withheld, conditioned or delayed, provided that:  (1) Tenant
complies with the provisions of Section 14.4; (2) Landlord declines to exercise
its rights under Section 14.3; (3) the Transferee is engaged in a business and
the portion of the Premises will be used for the Permitted Use in a manner which
is in keeping with the then standards of similar first class office buildings in
the Herndon-Dulles metropolitan area and does not conflict with any exclusive
use rights granted to any other tenant of the Building Complex; (4) the
Transferee has reasonable financial worth in light of the responsibilities
involved (taking into account Tenant's obligations under this Lease and the net
worth and creditworthiness of Tenant and other parties responsible for Tenant's
obligations under this Lease); (5) an Event of Default does not exist hereunder
at the time Tenant makes its request; (6) the Transferee is not a governmental
or quasi-governmental agency (if such quasi-governmental agency leases space
under contracting requirements of the General Services Administration of the
U.S. Government); and (7) the Transferee is not a tenant or currently
negotiating a lease with Landlord in the Dulles Executive Plaza Complex
(including the Building Complex) for space similar in size to the space proposed
to be Transferred by Tenant. Transfer includes a sale by Tenant of
substantially all of its assets or stock if Tenant is a publicly traded
corporation, a merger of Tenant with another corporation, the transfer of 49% or
more of the stock in a corporate tenant whose stock is not publicly traded, or
transfer of 49% or more of the beneficial ownership interests in a partnership
or limited liability company tenant. If any Alterations to the Premises or the
Common Areas are required by Applicable Laws in connection with such Transfer or
the particular business of such Transferee, such Alterations shall be subject to
the prior approval of Landlord (which approval shall not be unreasonably
withheld, conditioned or delayed) and Tenant shall bear the cost of such
Alterations.

       14.2 Following any Transfer in accordance with this Section 14, Landlord
may, after the occurrence of an Event of Default by Tenant and until such Event
of Default is cured, collect rent from the Transferee or occupant and apply the
net amount collected to the Rent, but no Transfer or collection will be deemed
an acceptance of the Transferee or occupant as Tenant or release Tenant from its
obligations. Consent to a Transfer shall not relieve Tenant from obtaining
Landlord's consent to any other Transfer. Notwithstanding Landlord's consent to
a Transfer, Tenant shall continue to be primarily liable for its obligations.
Solely with respect to subleases and assignments for which Landlord's consent is
required, if Tenant collects any rent or other amounts from a Transferee in
excess of the Rent and other amounts due under this Lease for any monthly
period, Tenant shall pay Landlord 50% of the excess monthly, as and when
received; provided, however, that all expenses incident to any assignment or
subletting, including brokerage fees, down time pending consummation of the
Transfer, reasonable attorneys' fees, abatements, the unamortized costs of the
Tenant Work in excess of the Allowance to the extent completed for such
subtenant in such

                                       10
<PAGE>

space (with interest at Tenant's cost of funds or, if the improvement is not
financed, at the prime rate reported in the Wall Street Journal on the date of
                                            -------------------
such expenditure) and similar inducements or expenses, shall be calculated and
amortized over the term of such sublease or assignment, and be reimbursed
monthly to Tenant out of the rent received by Tenant based on such amortization
prior to such division of any excess rent.

       14.3  Notwithstanding the above (and except for a Transfer permitted
under Section 14.7), if Tenant requests Landlord's consent to sublet 49% or more
of the Premises for all or substantially all of the remainder of the then-
current Term of the Lease or assign Tenant's interest in the Lease, Landlord may
refuse to grant such consent in its sole discretion and terminate this Lease as
to the portion of the Premises with respect to which such consent was requested;
provided, however, if Landlord does not consent and elects to terminate the
Lease as to such portion, Tenant may within 15 days after notice from Landlord
to this effect withdraw Tenant's request for consent. If such termination
occurs, it shall be effective on the date designated in a notice from Landlord
and shall not be more than 30 days following such notice.

       14.4  Tenant must notify Landlord at least 30 days prior to the desired
date of the Transfer ("Tenant's Notice"), excluding a Transfer permitted under
Section 14.7. Tenant's Notice shall describe the portion of the Premises to be
transferred and the terms and conditions. Landlord has, without obligation, 15
days following receipt of Tenant's Notice to (i) propose a subtenant for such
space (which subtenant shall be subject to reasonable approval of Tenant) or
(ii) exercise its rights pursuant to Section 14.3 if Tenant's Notice discloses
that 49% or more of the Premises is involved for all or substantially all of the
remainder of the then-current Term of the Lease. If the space covered by
Tenant's Notice is subleased to a sublessee proposed by Landlord, rent and other
sums due from the subtenant will be paid to Tenant directly and Landlord has no
responsibility for the performance by such subtenant of its obligations under
its sublease with Tenant. If Landlord does not exercise its rights under clause
(i) or clause (ii) within 15 days after receipt of Tenant's Notice, Landlord
shall be deemed to have waived its rights under those clauses with respect to
the proposed transaction and Tenant shall be free to sublet the specified
portion of the Premises to any third party on terms substantially identical to
those described in Tenant's Notice, subject to Landlord's consent as set forth
above. If Tenant does not sublet such portion of the Premises within 180 days
following Landlord's notice to Tenant, Tenant must reoffer the Premises to
Landlord in accordance with the provisions hereof prior to subleasing to a third
party.

       14.5  Tenant shall deliver to Landlord a fully-executed copy of each
agreement evidencing a sublease, assignment or mortgage within 10 business days
after the full execution thereof. Each sublease is subject to the condition
that if the Term of this Lease is terminated or Landlord succeeds to Tenant's
interest in the Premises by voluntary surrender or otherwise, at Landlord's
option the subtenant shall be bound to Landlord for the balance of the term of
such sublease and shall attorn to and recognize Landlord as its landlord under
the then executory terms of such sublease. Solely with respect to subleases and
assignments for which Landlord's consent is required, Tenant shall pay
Landlord's reasonable expenses, including reasonable attorneys' fees, of
determining whether to consent and in reviewing and approving the documents (up
to a maximum of $1,500). Solely with respect to subleases and assignments for
which Landlord's consent is required, Tenant shall provide Landlord with such
information as is reasonably necessary to make its determination pursuant to
Section 14.1.

       14.6  If a trustee or debtor in possession in bankruptcy is entitled to
assume control over Tenant's rights under this Lease and assigns such rights to
any third party notwithstanding the provisions hereof, the rent to be paid by
such party shall be increased to the current Base Rent (if greater than that
being paid for the Premises) which Landlord charges for comparable space in the
Building as of the date of such third party's occupancy. If Landlord is
entitled under the Bankruptcy Code to "Adequate Assurance" of future
performance of this Lease, the parties agree that such term includes the
following:

             (1) Any assignee must pay to Landlord at the time the next monthly
installment of Base Rent is due under this Lease, in addition to such
installment of Base Rent, an amount equal to the monthly installments of Base
Rent and additional rent due under this Lease for the next six months under this
Lease, said amount to be held by Landlord in escrow, with interest, until either
such assignee defaults in its payment of rent or other obligations under this
Lease (whereupon Landlord shall have the right to draw on such escrowed funds)
or until the expiration of this Lease (whereupon the funds shall be returned to
the Assignee within 30 days of the expiration of the Term of this Lease).

             (2) The assignee must assume and agree to be bound by the
provisions of this Lease.

       14.7. Notwithstanding anything to the contrary herein, Tenant may,
without obtaining Landlord's consent, make a Transfer to the following parties
(each a "Permitted Transferee") on the following conditions (a "Permitted
Transfer"): (1) any Affiliate of Tenant (as hereinafter defined) of which
Tenant owns more than a 25% interest; (2) any Parent of Tenant (as hereinafter
defined); (3) any Affiliate of Tenant's Parent; or (4) any entity into which
Tenant merges or consolidates or which purchases all or substantially all of the
assets or stock or ownership interests of Tenant; provided that the resulting
corporation has a net worth at least equal to Tenant's net worth as of the date

                                       11
<PAGE>

hereof; provided that: (i) Tenant remains primarily liable on its obligations
hereunder; (ii) the Transferee assumes and is bound by all obligations of Tenant
for payment of all amounts of Rent and other sums and the performance of all
covenants required by Tenant pursuant to this Lease; (iii) the Transferee
complies with the usage restrictions of this Lease; and (iv) not less than 15
days prior to the effective date of the Transfer, Tenant provides Landlord with
such evidence as Landlord may reasonably require to establish that the Transfer
meets the requirements of a Permitted Transfer (without such notice requiring
disclosure of the name of the entity with which Tenant is contemplating a merger
until such merger becomes effective). An "Affiliate of Tenant" or "Affiliate of
Tenant's Parent" shall mean any corporation, association, trust or partnership
(I) that Controls (as herein defined) Tenant or Tenant's Parent, or (II) that is
under the Control of Tenant or Tenant's Parent through stock ownership or
otherwise or (III) that is under common Control with Tenant or Tenant's Parent.
A "Parent of Tenant" shall mean any corporation, association, trust or
partnership (x) that Controls Tenant or (y) that owns more than fifty percent
(50%) of the issued and outstanding voting securities of Tenant. The terms
"Control" or "Controls" shall mean the power directly or indirectly to direct
the management or policies of Tenant or such other entity. Furthermore, Tenant
may allow employees of companies to whom Tenant is providing products or with
which Tenant is collaborating in the development or provision of products or
services (collectively referred to as "Collocation Services") to work in the
Premises without Landlord's consent and without being deemed to have sublet any
portion of the Premises, so long as such employees do not occupy space which is
separated from that occupied by Tenant by demising walls and the number of such
employees whose primary place of employment is the Premises does not exceed ten
percent (10%) of the total number of persons regularly occupying the Premises.

  15.  DAMAGE TO PROPERTY.  Tenant agrees Landlord is not liable for any
       ------------------
injury or damage, either proximate or remote, occurring through or caused by
fire, water, steam, or any repairs, alterations, injury, accident, or any other
cause to the Premises, to any furniture, fixtures, Tenant improvements, or other
personal property of Tenant kept or stored in the Premises, or in other parts of
the Building Complex, whether by reason of the negligence or default of
Landlord, other occupants, any other person, or otherwise; and the keeping or
storing of all property of Tenant in the Premises and Building Complex is at the
sole risk of Tenant.

  16.  INDEMNITY.
       ---------

       16.1 Tenant agrees to indemnify, defend, and hold Landlord and Building
Manager harmless from all liability, costs, or expenses, including reasonable
attorneys' fees and costs of litigation, on account of damage to the person or
property of any third party, including any other tenant in the Building Complex,
to the extent caused by the negligence or breach of this Lease by the Tenant,
Tenant's agents or employees, or any other person entering upon the Premises
under express or implied invitation of Tenant (collectively, "Tenant's
Agents").

       16.2 Tenant shall maintain throughout the Term a commercial general
liability policy, including protection against death, personal injury and
property damage, issued by an insurance company qualified to do business in the
state in which the Premises are located, with a single limit of not less than
$1,000,000.00.  Such policy shall name Landlord, Building Manager, and Mortgagee
as additional insureds, be primary to any other similar insurance of such
additional insureds, and provide that it may not be cancelled or modified
without at least 20 days' prior notice to Landlord and Mortgagee. The minimum
limits of such insurance do not limit the liability of Tenant hereunder. Prior
to occupancy of the Premises, and prior to expiration of the then-current
policy, Tenant shall deliver certificates evidencing that insurance required
under this Lease is in effect.

       16.3 Landlord agrees to indemnify, defend, and hold Tenant harmless from
all liability, costs, or expenses, including reasonable attorneys' fees and
costs of litigation, on account of damage to the person or property of any third
party (excluding Tenant's Agents), including any other tenant in the Building
Complex, to the extent caused by the negligence or breach of this Lease by
Landlord or Landlord's agents or employees.

  17.  SURRENDER AND NOTICE.  Upon the expiration or other termination of this
       --------------------
Lease, Tenant shall immediately quit and surrender to Landlord the Premises
broom clean, in good order and condition, ordinary wear and tear and loss by
fire or other casualty excepted, and Tenant shall remove: (i) all of its
movable furniture and other effects; (ii) all telephone cable within the
vertical risers and related equipment in the Building or Building Complex; (iii)
HVAC equipment, Communications Equipment, Backup System and Related Equipment
outside the Premises; and (iv) those Alterations required to be removed pursuant
to Section 12.3.  If Tenant fails to timely vacate the Premises as required,
Tenant is responsible to Landlord for all resulting costs and damages of
Landlord, including any amounts paid to third parties who are delayed in
occupying the Premises.

                                       12
<PAGE>

  18.  INSURANCE, CASUALTY, AND RESTORATION OF PREMISES.
       ------------------------------------------------

       18.1 Throughout the Term of the Lease, Landlord shall maintain standard
extended coverage property insurance for the Building Complex, the shell and
core of the Building and the Premises in an amount equal to the replacement cost
thereof (exclusive of the foundations). Throughout the Lease Term, Landlord
also shall maintain (a) commercial general liability insurance covering the
common areas of the Building in amounts at least as high as the greater of (i)
that required of Tenant in this Lease, and (ii) that required by Landlord's
lender, and (b) insurance for loss of Rent. The foregoing insurance policies
shall be from such companies, and on such terms and conditions as Landlord deems
appropriate, from time to time.

       18.2 Tenant shall maintain throughout the Term insurance coverage at
least as broad as ISO Special Form Coverage against risks of direct physical
loss or damage (commonly known as "all risk") for the full replacement cost of
Tenant's property and betterments in the Premises, including tenant finish in
excess of the Initial Tenant Finish.

       18.3 If the Building or Premises is damaged by fire or other casualty
which renders the Premises wholly or partially untenantable and the damage is so
extensive that an independent architect selected by Landlord certifies in
writing to Landlord and Tenant within 45 days of said casualty that the Premises
cannot, with the exercise of reasonable diligence, be made fit for occupancy
within the time period (the "Repair Period") that is the lesser of (a) 180
working days from the happening thereof and (b) one-fourth of the time remaining
in the Term of the Lease, then, at the option of Landlord or Tenant exercised in
writing to the other within 30 days of such determination, this Lease shall
terminate as of the occurrence of such damage. In the event of termination,
Tenant shall pay Rent duly apportioned up to the time of such casualty and
forthwith surrender the Premises and all interest. If Tenant fails to do so,
Landlord may reenter and take possession of the Premises and remove Tenant. If,
however, the damage is such that the architect certifies that the Premises can
be made tenantable within such Repair Period or neither Landlord or Tenant
elects to terminate the Lease despite the extent of damage, then the provisions
below apply.

       18.4 If the Premises are damaged by fire or other casualty that does not
render it untenantable or require a repair period in excess of the Repair
Period, Landlord shall with reasonable promptness except as hereafter provided
repair the Premises to the extent of the Initial Tenant Finish.

       18.5 If the Building is damaged (though the Premises may not be affected,
or if affected, can be repaired within the Repair Period) and within 60 days
after the damage Landlord decides not to reconstruct or rebuild the Building,
then, notwithstanding anything contained herein, upon notice to that effect from
Landlord within said 60 days, Tenant shall pay the Rent apportioned to such
date, this Lease shall terminate from the date of such notice, and both parties
discharged from further obligations except as otherwise expressly provided;
provided the leases of all other similarly affected tenants in the Building are
terminated and Landlord in fact does not repair or restore the damaged or
destroyed portions of the Building within the six (6)-month period following the
date of termination.

      18.6 Landlord and Tenant waive all rights of recovery against the other
and its respective officers, partners, members, agents, representatives, and
employees for loss or damage to its real and personal property kept in the
Building Complex which is capable of being insured against under ISO Special
Form Coverage, or for loss of business revenue or extra expense arising out of
or related to the use and occupancy of the Premises. Tenant also waives all such
rights of recovery against Building Manager. Each party shall notify their
insurance carrier that the foregoing waiver is contained in this Lease and
obtain an appropriate waiver of subrogation provision in their policies.

       18.7 Rent shall abate during any period of repair and restoration  in the
same proportion that the part of the Premises rendered untenantable bears to the
whole; provided, however, if the casualty is caused by the willful misconduct or
negligence of Tenant or Tenant's Invitees, then the Rent will abate during any
such period of repair and restoration but only to the extent of any recovery by
Landlord under its rental insurance related to the Premises.

  19.  CONDEMNATION.  If the Premises or substantially all of it or any
       ------------
portion of the Building Complex which renders the Premises untenantable is taken
by right of eminent domain, or by condemnation (which includes a conveyance in
lieu of a taking), this Lease, at the option of either Landlord or Tenant
exercised by notice to the other within 30 days after the taking, shall
terminate and Rent shall be apportioned as of the date of the taking. Tenant
shall forthwith surrender the Premises and all interest in this Lease, and, if
Tenant fails to do so, Landlord may reenter and take possession of the Premises.
If less than all the Premises is taken, Landlord shall promptly repair the
Premises as nearly as possible to its condition immediately prior to the taking,
unless Landlord elects not to rebuild under Section 18.5. Landlord shall
receive the entire award or consideration for the taking. Nothing contained
herein, however, shall prevent Tenant from pursuing a separate claim against the
condemning authority for the value of (i) Tenant's Alterations and improvements
to the extent paid for by Tenant and not paid for from the Finish Allowance,
(ii) Tenant's furnishings, equipment and trade fixtures installed in the
Premises at Tenant's expense, and (iii) for relocation

                                       13
<PAGE>

expenses, provided that such claim does not in any way diminish the award or
compensation payable to or recoverable by Landlord in connection with such
taking or condemnation.

  20.  DEFAULT BY TENANT.
       -----------------

       20.1 Each of the following events is an "Event of Default":

            (1)  Any failure by Tenant to pay Rent on the due date unless such
failure is cured within 5 business days after notice by Landlord; however,
Tenant is not entitled to more than 2 notices of delinquent payments during any
calendar year and, if thereafter during such calendar year any Rent is not paid
when due, an Event of Default shall automatically occur;

            (2)  Tenant  abandons the Premises (as evidenced by vacating the
Premises with the intent by Tenant not to be bound by the terms of the Lease, as
evidenced by a breach of any of its other obligations under the Lease, including
the payment of Rent);

            (3)  This Lease or Tenant's interest is transferred whether
voluntarily or by operation of law except as permitted in Section 14;

            (4)  This Lease or any part of the Premises is taken by process of
law and is not released within 15 days after a levy;

            (5)  Commencement by Tenant of a proceeding under any provision of
federal or state law relating to insolvency, bankruptcy, or reorganization
("Bankruptcy Proceeding");

            (6)  Commencement of a Bankruptcy Proceeding against Tenant, unless
dismissed within 60 days after commencement;

            (7)  The insolvency of Tenant or execution by Tenant of an
assignment for the benefit of creditors; the convening by Tenant of a meeting of
its creditors or any significant class thereof for purposes of effecting a
moratorium upon or extension or composition of its debts; or the failure of
Tenant generally to pay its debts as they mature, or the occurrence of any of
the foregoing with respect to any Guarantor, if any, of Tenant's obligations;

            (8)  The admission in writing by Tenant (or any general partner of
Tenant if Tenant is a partnership), that it is unable to pay its debts as they
mature or it is generally not paying its debts as they mature;

            (9)  Tenant fails to take possession of the Premises by the 9th day
following the Commencement Date (which deadline shall be extended by delays
beyond the reasonable control of Tenant, provided that Tenant is proceeding with
due diligence to complete the Tenant Work and move into the Premises);

            (10) Tenant fails to perform any of its other obligations and non-
performance continues for 30 days after notice by Landlord or, if such
performance cannot be reasonably had within such 30 day period, Tenant does not
in good faith commence performance within such 30 day period and diligently
proceed to completion; provided, however, Tenant's right to cure shall not
exceed the period provided by Applicable Law;

            (11)  Any event which is expressly defined as or deemed an Event of
Default under this Lease.

       20.2 Remedies of Landlord.  If an Event of Default occurs, Landlord may
            --------------------
then or at any time thereafter, either:

            (1) (a)  Without further notice except as required by Applicable
Laws, reenter and repossess the Premises or any part and expel Tenant and those
claiming through or under Tenant and remove the effects of both without being
deemed guilty of any manner of trespass and without prejudice to any remedies
for arrears of Rent or preceding breach of this Lease. Should Landlord reenter
or take possession pursuant to legal proceedings or any notice provided for by
Applicable Law, Landlord shall, from time to time, without terminating this
Lease, use commercially reasonable efforts to relet the Premises or any part,
either alone or in conjunction with other portions of the Building Complex, in
Landlord's or Tenant's name but for the account of Tenant, for such periods
(which may be greater or less than the period which would otherwise have
constituted the balance of the Term) and on such conditions and upon such other
terms (which may include concessions of free rent and alteration and repair of
the Premises) as Landlord, in its sole discretion, determines and Landlord may
collect the rents therefor. Landlord is not in any way responsible or liable
for failure to relet the Premises, or any part thereof, or for any failure to
collect any rent due upon such reletting, but Landlord shall use commercially
reasonable efforts to mitigate its damages.  If there is other unleased space in
the  Dulles Executive Plaza complex (consisting of the Dulles Executive Plaza I
and Dulles Executive Plaza II; collectively, the "Dulles Executive Plaza
Complex"), Landlord may lease such other space without prejudice to its
remedies against

                                       14
<PAGE>

Tenant. No such reentry or repossession or notice from Landlord shall be
construed as an election by Landlord to terminate this Lease unless specific
notice of such intention is given Tenant. Acts of maintenance or preservation or
efforts to relet the Premises or the appointment of a receiver upon initiative
of Landlord to protect Landlord's interest under this Lease shall not constitute
a termination of Tenant's contractual liability under this Lease unless written
release of liability is given by Landlord to Tenant. Landlord reserves the right
following any reentry and/or reletting to exercise its right to terminate this
Lease by giving Tenant notice, in which event this Lease will terminate as
specified in the notice.

                (b)  If Landlord takes possession of the Premises without
terminating this Lease, Tenant shall pay Landlord (i) the Rent which would be
payable if repossession had not occurred, less (ii) the net proceeds, if any, of
any reletting of the Premises after deducting all of Landlord's expenses
incurred in connection with such reletting, including all repossession costs,
brokerage commissions, attorneys' fees, expenses of employees, alteration, and
repair costs (collectively "Reletting Expenses"). If, in connection with any
reletting, the new lease term extends beyond the Term or the premises covered
thereby include other premises not part of the Premises, a fair apportionment of
the rent received from such reletting and the Reletting Expenses, will be made
in determining the net proceeds received from the reletting (i.e., if the
                                                             ----
Premises are relet for a period that is longer than the then remaining balance
of the Term of this Lease, then with respect to such costs incurred in reletting
the Premises, the costs for which Tenant shall be responsible shall be only a
fraction thereof, the numerator of which is the number of months then remaining
in the balance of the Term of the Lease, and the denominator of which is the
total number of months in the initial term of the replacement tenant's lease,
and/or if the Premises is relet as part of a larger premises, then with respect
to such costs incurred in reletting the Premises, the costs for which Tenant
shall be responsible shall be only a fraction thereof, the numerator of which is
the number of rentable square feet in the Premises, and the denominator of which
is the total number of rentable square feet being leased pursuant to the terms
of the replacement tenant's lease). In determining such net proceeds, rent
concessions will also be apportioned over the term of the new lease. Tenant
shall pay such amounts to Landlord monthly on the days on which the Rent would
have been payable if possession had not been retaken, and Landlord is entitled
to receive the same from Tenant on each such day; or

            (2) Give Tenant notice of termination of this Lease on the date
specified and, on such date, Tenant's right to possession of the Premises shall
cease and the Lease will terminate except as to Tenant's liability as hereafter
provided as if the expiration of the term fixed in such notice were the end of
the Term.  If this Lease terminates pursuant to this Section, Tenant remains
liable to Landlord for damages in an amount equal to the Rent which would have
been owing by Tenant for the balance of the Term had this Lease not terminated,
less the net proceeds, if any, of reletting of the Premises by Landlord
subsequent to termination after deducting Reletting Expenses.  Landlord may
collect such damages from Tenant monthly on the days on which the Rent would
have been payable if this Lease had not terminated and Landlord shall be
entitled to receive the same from Tenant on each such day. Alternatively, if
this Lease is terminated, Landlord at its option may recover forthwith against
Tenant as damages for loss of the bargain and not as a penalty an amount equal
to the worth at the time of termination of the excess, if any, of the Rent
reserved in this Lease for the balance of the Term over the then Reasonable
Rental Value of the Premises for the same period plus all Reletting Expenses
(the worth at the time being based on discounting to the net present value using
a discount factor equal to the then-applicable discount rate of the Federal
Reserve Bank). "Reasonable Rental Value" is the amount of rent Landlord can
obtain for the remaining balance of the Term.

       20.3 Cumulative Remedies.  Suits to recover Rent and damages may be
            -------------------
brought by Landlord, from time to time, and nothing herein requires Landlord to
await the date the Term would expire had there been no Event of Default or
termination, as the case may be. Each right and remedy provided for in this
Lease is cumulative and non-exclusive and in addition to every other right or
remedy now or hereafter existing at law or equity, including suits for
injunctive relief and specific performance. The exercise or beginning of the
exercise by Landlord of one or more rights or remedies shall not preclude the
simultaneous or later exercise by Landlord of other rights or remedies. All
costs incurred by Landlord to collect any Rent and damages or to enforce this
Lease are also recoverable from Tenant. If any suit is brought because of an
alleged breach of this Lease, the prevailing party is also entitled to recover
from the other party all reasonable attorneys' fees and costs incurred in
connection therewith.

       20.4 No Waiver.  No failure by Landlord or Tenant to insist upon strict
            ---------
performance of any provision or to exercise any right or remedy upon a breach
thereof, and no acceptance of full or partial Rent or any payment due during the
continuance of any breach constitutes a waiver of any such breach or such
provision, except by written instrument executed by Landlord and Tenant. No
waiver shall affect or alter this Lease but each provision hereof continues in
effect with respect to any other then existing or subsequent breach thereof.

       20.5 Bankruptcy.  Nothing contained in this Lease limits Landlord's right
            ----------
to obtain as liquidated damages in any bankruptcy or similar proceeding the
maximum amount allowed by law at the time such damages are to be proven, whether
such amount is greater, equal to, or less than the amounts recoverable, either
as damages or Rent, referred to in any of the preceding provisions of this
Section.  Notwithstanding anything in this Section to the contrary, any

                                       15
<PAGE>

proceeding described in Section 20.1(5),(6),(7) and (8) is an Event of Default
only when such proceeding is brought by or against the then holder of the
leasehold estate under this Lease.

       20.6 Late Payment Charge.  Any Rent not paid within 5 days after the due
            -------------------
date shall thereafter bear interest at 5 percentage points above the Prime Rate
or the highest rate permitted by law, whichever is lower, until paid. Further,
if such Rent is not paid within 5 days after notice, Tenant agrees Landlord will
incur additional administrative expenses, the amount of which will be difficult
to determine; Tenant therefore shall also pay Landlord a late charge of 5% of
such payment for each late payment that remains unpaid for 5 days following
notice to Tenant. Any amounts paid by Landlord to cure an Event of Default of
Tenant which Landlord has the right but not the obligation to do, shall, if not
repaid by Tenant within 5 days of demand by Landlord, thereafter bear interest
at 5 percentage points above the Prime Rate until paid. "Prime Rate" means
that rate published from time to time in the Wall Street Journal as the prime
rate on the date closest to the date interest commences.

       20.7 Waiver of Jury Trial.  Tenant and Landlord waive any right to a
            --------------------
trial by jury in suits arising out of or concerning the provisions of this
Lease.

  21.  DEFAULT BY LANDLORD.  In the event of any alleged default on the part
       -------------------
of Landlord, Tenant shall give notice to Landlord and afford Landlord a
reasonable opportunity to cure such default. Such notice shall be ineffective
unless a copy is simultaneously also delivered in the manner required in this
Lease to any holder of a mortgage and/or deed of trust affecting all or any
portion of the Building Complex (collectively, "Mortgagee"), provided that
prior to such notice Tenant has been notified (by way of notice of Assignment of
Rents and Leases, or otherwise), of the address of a Mortgagee. If Landlord
fails to cure such default within the time provided, then Mortgagee shall have
an additional 30 days following a second notice from Tenant or, if such default
cannot be cured within that time, such additional time as may be necessary
provided within such 30 days, Mortgagee commences and diligently pursues a cure
(including commencement of foreclosure proceedings if necessary to effect such
cure). If such default is in Landlord's failure to make repairs, provide
essential services or pay utility bills as are required under this Lease, then
following such applicable cure period, Tenant may (but shall not be obligated
to) make such repairs (in such manner as to not to void applicable warranties),
provide services or pay such bills as are reasonably required to cure such
default on behalf of Landlord and Landlord shall reimburse Tenant within 30 days
of receipt of Tenant's invoice the full amount of such reasonable out-of-pocket
cost and expense incurred by Tenant; provided, however, that if Landlord
disputes that such default exists or disputes the reasonableness of the amount
to be paid, by notice to Tenant prior to the expiration of the 30 day period,
then Landlord shall have no obligation to pay such amount until Tenant has
obtained a final non-appealable court judgment that such sum was due and payable
to Tenant under the terms of this Section 21 and wrongfully withheld by
Landlord. If any such repairs will affect the HVAC, plumbing, electrical or
mechanical systems of the Building (the "Building Systems"), the structural
integrity of the Building, or the exterior appearance of the Building, Tenant
shall use only those contractors used by Landlord in the Building for work on
the Building Systems, or its structure, and Landlord shall provide Tenant (upon
Tenant's request) with notice identifying such contractors and any changes to
the list of such contractors, unless such contractors are unwilling or unable to
perform such work or the cost of such work is not competitive, in which event
Tenant may utilize the services of any other qualified contractors which
normally and regularly performs similar work on comparable buildings. To the
extent any sum thus reimbursed to Tenant by Landlord represents an amount that
would have been included in the Operating Expenses of the Building if paid by
Landlord to perform the obligation in question, Landlord shall be entitled to
include in Operating Expenses the sum reimbursed to Tenant. Tenant's sole
additional remedy will be equitable relief or actual damages but in no event is
Landlord or any Mortgagee responsible for consequential damages or lost profit
incurred by Tenant as a result of any default by Landlord. If a Mortgagee, or
transferee under such Mortgage (hereafter defined), succeeds to Landlord's
interest as a result of foreclosure or otherwise, such party shall not be: (i)
liable for any default, nor subject to any setoff or defenses that Tenant may
have against Landlord (but such limitation shall not relieve such party from the
responsibility to perform the obligations as successor to Landlord ongoing
during its period of ownership); (ii) bound by any amendment (including an
agreement for early termination) without its consent made at any time after
notice to Tenant that such Mortgage requires such consent; and (iii) bound by
payment of Rent in advance for more than 30 days. Tenant agrees to pay Rent
(and will receive credit under this Lease) as directed in any Mortgagee's notice
of Landlord's default under the Mortgage reciting that Mortgagee is entitled to
collect Rent.

  22.  SUBORDINATION AND ATTORNMENT.
       ----------------------------

       22.1 This Lease at Landlord's option will be subordinate to any mortgage,
deed of trust and related documents now or hereafter placed upon the Building
Complex (including all advances made thereunder), and to all amendments,
renewals, replacements, or restatements thereof (collectively, "Mortgage").
Tenant agrees that no documentation other than this Lease is required to
evidence such subordination.

       22.2 If any Mortgagee elects to have this Lease superior to the lien of
its Mortgage and gives notice to Tenant, this Lease will be deemed prior to such
Mortgage whether this Lease is dated prior or subsequent to the date of such
Mortgage or the date of recording thereof.

                                       16
<PAGE>

       22.3 In confirmation of subordination or superior position, as the case
may be, Tenant will execute such documents as may be required by Mortgagee
(provided that such documents only confirm such subordination and do not in any
way modify the terms of this Lease) and if it fails to do so within 10 days
after demand, such failure shall be deemed an Event of Default hereunder.

       22.4 Tenant hereby attorns to all successor owners of the Building,
whether such ownership is acquired by sale, foreclosure of a Mortgage, or
otherwise; provided, however, that after succeeding to Landlord's interest under
this Lease, any such successor owner assumes in accordance with the terms of
this Lease and during its period of ownership all obligations of Landlord
arising after the date such successor owner acquires title to the Buildings.

       22.5 Within 30 days following the effective date of this Lease (full
execution of the Lease) and execution of a non-disturbance agreement by Tenant
in the form attached hereto as Exhibit F, Landlord will obtain a non-disturbance
agreement from Landlord's present Mortgagee in the form attached hereto as
Exhibit F; Tenant's agreement to subordinate under Section 22.1 above as to any
future Mortgagee is conditioned upon Tenant obtaining a non-disturbance
agreement from any such future Mortgagee of the Real Property and/or the
Building on such Mortgagee's standard form for such purposes substantially in
the form attached hereto as Exhibit F, with changes as such future Mortgagee may
reasonably require so long as such changes do not in any way modify the terms of
this Lease.

  23.  REMOVAL OF TENANT'S PROPERTY.
       ----------------------------

       23.1 All movable personal property of Tenant not removed from the
Premises upon vacation, abandonment, or termination of this Lease shall be
conclusively deemed abandoned and may be sold, or otherwise disposed of by
Landlord upon 10 days prior notice to Tenant therefor; Tenant shall pay
Landlord's reasonable expenses in connection with such disposition, provided
that Landlord delivers to Tenant a reasonably detailed statement of such
expenses.

       23.2 Landlord expressly waives all contractual and statutory rights of
distraint, liens, and security interests in Tenant's property, but such waiver
shall not preclude Landlord from obtaining a judgment lien.

  24.  HOLDING OVER: TENANCY MONTH-TO-MONTH.   If, after the expiration or
       ------------------------------------
termination of this Lease, Tenant remains in possession of the Premises without
a written agreement as to such holding over and continues to pay rent and
Landlord accepts such rent, such possession is a tenancy from month-to-month,
subject to all provisions hereof but at a monthly rent equivalent to 150%  of
the monthly Rent paid by Tenant immediately prior to such expiration or
termination. Rent shall continue to be payable in advance on the first day of
each calendar month. Such tenancy may be terminated by either party upon 10
days' notice prior to the end of any monthly period. Nothing contained herein
obligates Landlord to accept rent tendered after the expiration of the Term or
relieves Tenant of its liability under Section 17.

  25.  PAYMENTS AFTER TERMINATION.  No payments by Tenant after expiration or
       --------------------------
termination of this Lease or after any notice (other than a demand for payment
of money) by Landlord to Tenant reinstates, continues, extends the Term, or
affects any notice given to Tenant prior to such payments. After notice,
commencement of a suit, or final judgment granting Landlord possession of the
Premises, Landlord may collect any amounts due or otherwise exercise Landlord's
remedies without waiving any notice or affecting any suit or judgment.

  26.  STATEMENT OF PERFORMANCE.  Tenant agrees at any time upon not less
       ------------------------
than 10 days' notice to execute and deliver to Landlord a written statement (a)
stating that this Lease is unmodified and in full force and effect (or, if there
have been modifications, that the same is in full force and effect as modified
and stating the modifications); (b) stating whether or not, to the best
knowledge of Tenant (but without the requirement of an independent
investigation), there have been any defaults by Landlord or Tenant and any event
which with the giving of notice or passage of time, or both, would constitute
such a default (or, if there have been defaults, setting forth the nature
thereof); (c) stating the date to which Rent has been paid in advance; and (d)
such other information as Landlord reasonably requests, none of which shall
modify the Lease.  Such statement may be relied upon by a prospective purchaser
of Landlord's interest or Mortgagee. If Tenant fails to respond to Landlord
within such 10 day period and Tenant also fails to respond to Landlord within 5
days after Tenant's receipt of a second written request for Tenant's approval,
which second request states in bold capital letters that Tenant's failure to
respond as required by Section 26 of the Lease shall be deemed an Event of
Default under the Lease if Tenant fails to respond in 5 days, then an Event of
Default shall be deemed to have occurred hereunder. Upon request, Tenant will
furnish Landlord an appropriate resolution confirming that the party signing the
statement is authorized to do so. Landlord agrees, upon not less than 15 days
prior notice by Tenant, to execute, acknowledge and deliver to Tenant a
statement in writing (i) certifying that this Lease has been unmodified since
its execution and is in full force and effect (or if there have been
modifications, that the Lease is in full force and effect, as modified, and
stating the modifications), (ii) stating the dates, if any, to which the rent
and sums hereunder have been paid by Tenant, and (iii) stating whether or not to
the actual knowledge of Landlord, without independent

                                       17
<PAGE>

investigation or inquiry, there are then existing any defaults under this Lease
(and, if so, specifying the same). Such statement may be relied upon by any
approved, prospective assignee or subtenant.

  27.  MISCELLANEOUS.
       -------------

       27.1  Transfer by Landlord.  The term "Landlord" means so far as
             --------------------
obligations of Landlord are concerned, only the owner of the Building at the
time in question and, if any transfer of the title occurs, Landlord herein named
(and in the case of any subsequent transfers, the then grantor) is automatically
released from and after the date of such transfer of all liability as respects
performance of any obligations of Landlord thereafter to be performed. Any
funds in Landlord's possession at the time of transfer in which Tenant has an
interest will be turned over to the grantee and any amount then due Tenant under
this Lease will be paid to Tenant.

       27.2  No Merger.  The termination or mutual cancellation of this Lease
             ---------
will not work a merger, and such termination or cancellation will at the option
of Landlord either terminate all subleases or operate as an automatic assignment
to Landlord of such subleases.

       27.3  Common Area Use.  Landlord may use any of the Common Areas for the
             ---------------
purposes of completing or making repairs or alterations in any portion of the
Building Complex; provided, however, that in the exercise of such right Landlord
shall not unreasonably interfere with Tenant's use and occupancy of, or access
to, the Premises.

       27.4  Independent Covenants.  This Lease is to be construed as though the
             ---------------------
covenants between Landlord and Tenant are independent and not dependent and
Tenant is not entitled to any setoff of the Rent against Landlord if Landlord
fails to perform its obligations except as otherwise expressly set forth herein;
provided, however, the foregoing does not impair Tenant's right to commence a
separate suit against Landlord for any default by Landlord so long as Tenant
complies with Section 21.

       27.5  Validity of Provisions.  If any provision is invalid under present
             ----------------------
or future laws, then it is agreed that the remainder of this Lease is not
affected and that in lieu of each provision that is invalid, there will be added
as part of this Lease a provision as similar to such invalid provision as may be
possible and is valid and enforceable.

       27.6  Captions.  The caption of each Section is added for convenience
             --------
only and has no effect in the construction of any provision of this Lease.

       27.7  Construction.  The parties waive any rule of construction that
             ------------
ambiguities are to be resolved against the drafting party.  Any words following
the words "include," "including," "such as," "for example," or similar words or
phrases shall be illustrative only and are not intended to be exclusive, whether
or not language of non-limitation is used.

       27.8  Applicability.  Except as otherwise provided, the provisions of
             -------------
this Lease are applicable to and binding upon Landlord's and Tenant's respective
heirs, successors and assigns. Such provisions are also considered to be
covenants running with the land to the fullest extent permitted by law.

       27.9  Authority.  Tenant and Landlord and the party executing this Lease
             ---------
on behalf of each of Tenant and Landlord represent to the other party that such
party is authorized to do so by requisite action of Tenant or Landlord, as
applicable, and agree, upon request, to deliver a resolution, similar document,
or opinion of counsel to that effect.

       27.10 Severability.  If there is more than one party which is the Tenant
             ------------
or Landlord, the obligations imposed upon such party are joint and several.

       27.11 Acceptance of Keys, Rent or Surrender.  No act of Landlord or its
             -------------------------------------
representatives during the Term, including any agreement to accept a surrender
of the Premises or amend this Lease, is binding on Landlord unless such act is
by a partner, member or officer of Landlord, as the case may be, or other party
designated in writing by Landlord as authorized to act. The delivery of keys to
Landlord or its representatives will not operate as a termination of this Lease
or a surrender of the Premises. No payment by Tenant of a lesser amount than
the entire Rent owing is other than on account of such Rent nor is any
endorsement or statement on any check or letter accompanying payment an accord
and satisfaction. Landlord may accept payment without prejudice to Landlord's
right to recover the balance or pursue any other remedy available to Landlord.

       27.12 Building Name and Size.  Landlord may as it relates to the Building
             ----------------------
and Building Complex: change the name, increase the size by adding additional
real property, construct other buildings or improvements, change the location
and/or character, or make alterations or additions provided that such changes do
not result in more than a de minimus reduction in the rentable square footage of
the Premises or materially and adversely interfere with Tenant's use or
occupancy of or access to the Premises or cause the level of service required
under Section 7 to be reduced other than on a temporary basis.  If additional
buildings are constructed or the size is increased, Landlord and Tenant shall

                                       18
<PAGE>

execute an amendment which incorporates any necessary modifications to Tenant's
Pro Rata Share. Tenant may not use the Building's name for any purpose other
than as part of its business address.

       27.13 Diminution of View.  Tenant agrees that no diminution of light,
             ------------------
air, or view from the Building entitles Tenant to any reduction of Rent under
this Lease, results in any liability of Landlord, or in any way affects Tenant's
obligations.

       27.14 Limitation of Liability.  Notwithstanding anything to the contrary
             -----------------------
contained in this Lease, Landlord's liability is limited to Landlord's interest
in the Building (including Landlord's interest in any undistributed rents) and
any undistributed insurance or condemnation proceeds that were not applied as
required by this Lease, or any proceeds resulting from a sale of the Building if
such sale is made while a lawsuit is pending against Landlord by Tenant (and
only to the extent of any judgment resulting from such lawsuit), and Landlord
shall never be personally liable for recovery of any judgment. In the event
Tenant institutes an independent action against Landlord and is awarded a money
judgment for which a lien is of record, and provided that such judgment is
either affirmed on appeal by the highest court for which an appeal thereof may
be filed or the time for filing such an appeal has expired, then in such event,
and only in such event, Tenant may deduct the amount of such money judgment for
which a lien is of record from the next monthly installment or installments of
Base Rent due hereunder subject to the rights of Mortgagee.

       27.15 Non-Reliance.  Tenant confirms it has not relied on any statements,
             ------------
representations, or warranties by Landlord or its representatives except as set
forth herein.

       27.16 Written Modification.  No amendment or modification of this Lease
             --------------------
is valid or binding unless in writing and executed by the parties.

       27.17 Lender's Requirements.  In the event that any lender providing
             ---------------------
permanent financing or any refinancing for the Building requires, as a condition
of such financing, that modifications to this Lease be obtained, and provided
that such modifications (a) are reasonable, (b) do not adversely affect in a
material manner Tenant's use of the Premises as herein permitted, (c) do not
increase the rent and other sums to be paid by Tenant hereunder, and (d) do not
diminish any of Tenant's other rights under this Lease (including the type,
quantity, and quality of services Landlord is required to provide under this
Lease) or materially increase Tenant's obligations or decrease Tenant's rights,
Landlord may submit to Tenant a written amendment to this Lease incorporating
such required changes. Tenant hereby covenants and agrees to execute,
acknowledge and deliver such amendment to Landlord within 15 days of Tenant's
receipt thereof.

       27.18 Effectiveness.  Submission of this instrument for examination or
             -------------
signature by Tenant does not constitute a reservation of or option to lease and
it is not effective unless and until execution and delivery by both Landlord and
Tenant.

       27.19 Survival.  This Lease, notwithstanding expiration or termination,
             --------
continues in effect as to any provisions requiring observance or performance
subsequent to termination or expiration.

       27.20 Time of Essence.  Time is of the essence herein.
             ---------------

       27.21 Rules and Regulations.  Tenant and Tenant's agents, employees, and
             ---------------------
contractors shall at all times abide by the rules and regulations attached
hereto as Exhibit E. Landlord shall use reasonable efforts to enforce all such
rules and regulations, including any exceptions thereto, uniformly and in a
manner which does not unreasonably discriminate against Tenant, or increase
Tenant's monetary obligations under this Lease. If there is any inconsistency
between this Lease and the rules set forth in Exhibit E, this Lease shall
govern.

       27.22 Recording.  Tenant will not record this Lease. Recording of the
             ---------
Lease by or on behalf of Tenant is an Event of Default.

       27.23 Deed of Lease.  For purposes of Section 55-2, Code of Virginia
             -------------
(1950), as amended, this Lease is and shall be deemed to be a deed of lease.

  28.  AUTHORITIES FOR ACTION AND NOTICE.
       ---------------------------------

       28.1 Unless otherwise provided, Landlord may act through Landlord's
Building Manager or other designated representatives from time to time.

       28.2 All notices or other communications required or desired to be given
to Landlord must be in writing and shall be deemed received when delivered
personally to any officer, partner, or member of Landlord (depending upon the
nature of Landlord) or the manager of the Building (the "Building Manager")
whose office is in the Building, or when deposited in the United States mail,
postage prepaid, certified or registered, return receipt requested, addressed as

                                       19
<PAGE>

set forth in Section 1.10. All notices or communications required or desired to
be given to Tenant shall be in writing and deemed duly served when delivered
personally to any officer, employee, partner, or member of Tenant (depending
upon the nature of Tenant), individually if a sole proprietorship, or manager of
Tenant whose office is in the Building, or when deposited in the United States
mail, postage prepaid, certified or registered, return receipt requested,
addressed to the appropriate address set forth in Section 1.13. Either party may
designate in writing served as above provided a different address to which
notice is to be mailed. The foregoing does not prohibit notice from being given
as provided in the rules of civil procedure, as amended from time to time, for
the state in which the Real Property is located.

  29.  PARKING.  Landlord will make available the number of parking spaces set
       -------
forth in Section 1.9, in surface parking areas or garage parking areas,
respectively. All parking spaces shall be in and out, non-assigned parking
spaces in the designated areas for the respective spaces; the garage parking
spaces shall be non-assigned unreserved spaces in the uncovered portion of the
garage. Tenant shall pay the current monthly rate charged for each such space,
as it may change from time to time; provided, however, that all of the surface
or uncovered garage spaces shall be provided to Tenant without charge of parking
fees during the Initial Term. Tenant shall have the right to elect separately
to license reserved covered garage spaces on the 1st level on an availability
basis at Landlord's then-current parking rate for such spaces as it may change
from time to time; provided that future increases in any charged after the first
Lease Year shall be competitively priced and shall not exceed the prevailing
market rates in the Herndon-Dulles metropolitan area. Notwithstanding the
above, the right granted to Tenant to use such spaces is a license only and
Landlord's inability to make such spaces available at any time for reasons
beyond Landlord's reasonable control is not a material breach by Landlord of its
obligations hereunder and Tenant has no rights to use the parking garage except
as provided in this Section. The abatement of Tenant's obligation to pay for
unavailable spaces during any period of unavailability constitutes Tenant's sole
remedy. Tenant's failure to timely pay a parking bill shall constitute an Event
of Default hereunder. All vehicles parked in the parking facilities and the
personal property therein shall be at the sole risk of Tenant, Tenant's Agents
and the users of such spaces and Landlord shall have no liability for loss or
damage thereto for whatever cause.

  30.  SUBSTITUTE PREMISES. [INTENTIONALLY DELETED]
       -------------------

  31.  BROKERAGE.  Tenant and Landlord each represents it has not employed any
       ---------
broker with respect to this Lease and has no knowledge of any broker's
involvement in this transaction except those listed in Sections 1.15 and 1.16
(collectively, the "Brokers"). Landlord shall pay the Brokers a commission
pursuant to a separate agreement between each such Broker and Landlord. Tenant
shall indemnify Landlord against any expense incurred by Landlord as a result of
any claim for commissions or fees by any other broker, finder, or agent, whether
or not meritorious, employed by Tenant or claiming by, through, or under Tenant,
other than the Brokers. Landlord shall indemnify Tenant against any expense
incurred by Tenant as a result of any claim for commissions or fees by any other
broker, finder, or agent, whether or not meritorious, employed by Landlord or
claiming by, through, or under Landlord, other than the Brokers. Tenant
acknowledges Landlord is not liable for any representations by the Brokers
regarding the Premises, Building, Building Complex, or this Lease.

  32.  COUNTERPARTS.  This Lease may be executed in two or more counterparts,
       ------------
each of which shall be deemed an original, but all of which together shall
constitute one and the same instrument. Any one or more counterpart signature
pages may be removed from one counterpart of the Lease and annexed to another
counterpart of the Lease to form a completely executed original instrument
without impairing the legal effect of the signature thereon.

  33.  ADDENDUM/EXHIBITS.  Any Addenda and/or Exhibits referred to herein and
       -----------------
attached hereto are incorporated herein by reference.

                                       20
<PAGE>

  IN WITNESS WHEREOF, the parties have executed this Lease as of the day and
year first above written and it is effective upon delivery of a fully-executed
copy to Tenant.

LIFEMINDERS.COM, INC., a Delaware       DTC ASSOCIATES, LLC, a Virginia limited
corporation                             liability company

By:                                     By:

Print Name:                                          Authorized Signatory

Print Title:
                                                          "Landlord"
ATTEST:

By:

Print Name:

Print Title:

                        "Tenant"

                                       21
<PAGE>

                                   ADDENDUM

  THIS ADDENDUM is to that certain lease agreement (the "Lease") by and between
DTC ASSOCIATES, LLC, a Virginia limited liability company ("Landlord"), and
LIFEMINDERS.COM, INC., a Delaware corporation ("Tenant"), with respect to
approximately 131,841 rentable square feet of space (the "Premises") in the
Building.  In the event of any conflict between the terms and provisions of the
Lease and the terms and provisions of this Addendum, the terms and provisions of
this Addendum shall control.

  1. Landlord and Tenant agree that the Rentable Area of the Building and the
rentable square footage of the Premises have been verified from Landlord's
Drawings (as defined in the Work Letter).  Upon completion of construction of
the Building Improvements, Landlord shall have Landlord's Architect verify
whether the as-built Building varied from the Landlord's Drawings so as to alter
the calculation of the Rentable Area or of the rentable square footage of the
Premises, calculated on the same basis as used in calculating the initial
measurement approved by Landlord and Tenant (determined by measuring the usable
area in accordance with the June 7, 1996 American National Standards Institute
(ANSI)/Building Owners and Managers Association (BOMA) standard method of
measurement of floor area for multi-tenanted office buildings).  If Landlord's
Architect determines that such a variance exists (which determination shall be
subject to the reasonable approval of Tenant's architect), there shall be an
adjustment to reflect such re-measurement and recalculation of the Base Rent
(based on the annually per rentable square foot rates set forth in Section 1.4),
Tenant's Pro Rata Share, the Finish Allowance (based on $27.50 per rentable
square foot) and the number of parking spaces to which Tenant is entitled (based
on a ratio of 4 parking spaces per 1,000 usable square feet of space leased, of
which 20 shall be unassigned uncovered garage spaces).  If the amount of Base
Rent payable for such period exceeds the amount theretofore paid by Tenant,
Tenant shall pay the amount of such excess to Landlord within 30 days of written
demand thereof from Landlord.  If the amount of Base Rent payable for such
period is less than the amount theretofore paid by Tenant, Landlord shall credit
the same to the next payment of Base Rent due hereunder.

  2. Throughout the Term of this Lease, Tenant shall have the right to have
Tenant's name identification signage on the top spandrels of the Building
generally as depicted on the attached Exhibit H (the "Signage").  The Signage is
subject to approval by Landlord (which approval shall not be unreasonably
withheld, conditioned or delayed; Landlord acknowledges that it has approved the
signage generally as depicted on the attached Exhibit H, subject to verification
of installation details and methods of attachment) and the applicable
governmental officials and under the Declaration and no Signage shall be
permitted if such approval is not obtained. Landlord and Tenant agree to
cooperate reasonably to seek approval of the Signage from the applicable
governmental authorities and under the Declaration. Tenant shall bear the costs
of fabricating and installing the such Signage and will bear the costs of
removal of the Signage at the termination or expiration of the Lease, including
restoring or repairing damages to the Building caused by such removal to the
condition at the time of installation. In addition, if Landlord is required at
any time to remove any Signage, including any approved Signage, due to any
Applicable Law or if Tenant elects to remove or change the Signage at any time,
Tenant shall bear the costs of such change or removal. Tenant will be
responsible at its cost to maintain its Signage in a condition consistent with
the maintenance provided for similar signage in the Herndon-Dulles metropolitan
area. In addition to the Signage, Landlord, at Landlord's sole cost and expense,
shall also provide Tenant with Building Standard directory signage on the
Building's directory board in the lobby of the Building and any other directory
which may become a part of the Building Complex. The Signage rights granted to
Tenant pursuant to this Paragraph (not including Building directory signage) are
personal to Tenant, provided that Tenant may assign its Signage rights to
Permitted Transferees under Section 14.7 and any assignees or subtenants for
which Landlord has termination rights pursuant to Section 14.3 but for which
Landlord does not exercise such rights. Landlord shall not grant rights to
identification signage on the Building spandrel or on the exterior walls of the
Building to other tenants.

  3. Landlord grants Tenant an option (the "Option") to extend the term of the
Lease for one (1) additional term of five (5) years (the "Option Term")
commencing immediately after expiration of the Initial Term of this Lease.  The
Option applies only to the Premises and is on the following conditions:

     A.   Notice of Tenant's interest in exercising the Option must be given to
Landlord no earlier than 12 months and no later than 9 months prior to the
Expiration Date ("Tenant's Notice").  Not later than thirty (30) days after
receiving Tenant's Notice, Landlord will notify Tenant of the Base Rent
applicable during the Option Term in accordance with subparagraph D below
("Landlord's Notice").  If the Tenant's notice is not given timely, Tenant's
Option with respect to the Option Term shall lapse and be of no further force or
effect.

     B.   Tenant shall have 15 days following Tenant's receipt of Landlord's
Notice within which to provide notice to Landlord electing (i) to exercise the
Option for the Option Term by delivering notice of such exercise to Landlord at
the Base Rent, allowances and concessions, if any, set forth in Landlord's
Notice, (ii) to exercise the Option for the Option Term but reserving the right
to final determination of the Base Rent to be paid in accordance with

                                       1
<PAGE>

subparagraph D  below ("Tenant's Dispute Notice"), or (iii) to rescind its
exercise of the Option for the Option Term.  If Tenant timely elects (i) first
above, the Lease shall be deemed extended and thereafter the parties shall
execute an amendment to the Lease setting forth the extension for the Option
Term and the rental rate applicable during the Option Term.  If Tenant timely
elects (ii) first above, the parties shall have 30 days after the date Tenant
delivers its Tenant's Dispute Notice to Landlord in which to agree on the Base
Rent, escalation factor and additional rent which shall be payable during the
Option Term.  If during such 30-day period the parties agree on such Base Rent,
escalation factor and additional rent payable during each year of the Option
Term, then during such period they shall execute an amendment to this Lease
stating the rent so agreed upon.  If during such period the parties do not for
any reason whatsoever agree in writing upon such rent, then the Base Rent,
escalations, additional rent, and concessions shall be determined in accordance
with subparagraph D below.  If Tenant fails to timely make any election, Tenant
shall be deemed to have elected (ii) first above (i.e., Tenant shall have been
deemed to have timely delivered the Tenant's Dispute Notice). If Tenant elects
(iii) first above, Tenant's right to renew the Term of the Lease shall lapse and
be of no further force or effect.

     C.   Tenant's right to exercise the Option is conditioned on: (i) there not
being an Event of Default hereunder at the time of exercise or at the time of
commencement of the Option Term;  (ii) Tenant not having subleased or vacated
more than 50% of the Premises to other than Permitted Transferees as of the
commencement of the Option Term; (iii) Tenant not having assigned its interest
under the Lease as of the commencement of the Option Term to other than a
Permitted Transferee; and (iv) Tenant having the financial ability to perform
its obligations under the Option Term as evidenced by maintenance of the Letter
of Credit (as referred to below).  Upon an assignment of the Lease to other than
a Permitted Transferee, this Paragraph is null and void.

     D.   If following delivery of Tenant's Dispute Notice, Landlord and Tenant
have not agreed upon the terms as of the 30th day after the date of Tenant's
Dispute Notice,  then Landlord and Tenant shall, within 5 days thereafter, agree
upon a qualified commercial real estate broker of good reputation, having at
least 5 years' experience in the northern Virginia real estate market; if
Landlord and Tenant cannot agree upon the broker, then they shall each select,
within the foregoing 5-day period, a real estate broker who meets the above
qualifications and together such brokers will then select as the arbitrator a
real estate broker who meets the above qualifications (the broker selected shall
be deemed the "Arbitrator" hereunder). Within 10 days of selection of the
Arbitrator, Landlord and Tenant each shall state, in writing, their
determination of the Prevailing Market Rental Rate supported by the reasons
therefor and shall make counterpart copies for each other and the Arbitrator,
under an arrangement for simultaneous exchange of the determinations. The
Arbitrator will review each party's declaration of the Prevailing Market Rental
Rate and select the one which he determines most accurately reflects such
Arbitrator's determination of the Prevailing Market Rental Rate. The Arbitrator
shall have no right to propose a middle ground or any modifications of either of
the two proposed resolutions. The Base Rent to paid during the Option Term shall
be the Prevailing Market Rental Rate so determined and Tenant shall have the
right to receive the allowance and concessions, if any, set forth in Landlord's
Notice; provided, however, that if there are at least 7 full months remaining in
the balance of the initial Term of the Lease as of the date of the Arbitrator's
determination, then Tenant shall have the right to rescind its election to
extend the Lease for the Option Term by notice to Landlord within 2 business
days (time being strictly of the essence thereto) after the date of the
Arbitrator's determination, in which event the Lease shall expire at the end of
the Initial Term of the Lease (unless sooner terminated in accordance with this
Lease).  Landlord and Tenant shall each bear the cost of its broker and shall
share equally the cost of the Arbitrator; provided that if Tenant has elected to
rescind its election to extend the Lease for the Option Term pursuant to the
previous sentence, Tenant shall bear the costs of all 3 brokers.  For purposes
of this Paragraph, Prevailing Market Rental Rate shall mean the annual amount
per square foot (including the then-current Operating Expenses) that a willing
tenant would pay and a willing landlord would accept following arms-length
negotiations with respect to an "Assumed Lease" (as defined below) under the
circumstances then obtaining.  "Assumed Lease" means (i) a lease or renewal
having a commencement date within 6 months of Tenant's Notice for space of
approximately the same size as the Premises of the Building or a "Comparable
Building," as hereinafter defined, located in a portion of the Building or such
Comparable Building, and with a view and floor height similar to the portion of
the Premises for which Prevailing Market Rental Rate is being determined, for a
term equal in length to the Option Term; (ii) assuming that a real estate
commission is payable with respect to such lease to the extent a third-party
commission with respect to extension is agreed or obligated to be paid by
Landlord with respect to the Option Term; and (iii) taking into consideration
and making adjustment to reflect allowances and concessions provided in
Landlord's Notice, if any, and the use of the Base Operating Expenses provided
in Section 1.5 during the Option Term (including whether or not the Base Year is
changed).  "Comparable Building" shall mean any existing buildings or buildings
hereafter constructed in the Dulles corridor of northern Virginia which is of a
size, location, quality and prestige comparable to, and with a size and
efficiency of floor plate, amenities, and with tenants of a stature reasonably
comparable with the Building, provided that appropriate adjustments shall be
made to adjust for differences in the size, location, age, efficiency of
floorplate, and quality between such other buildings and the Building.

     E.   After exercise, or failure to exercise the Option, Tenant shall have
no further rights to extend the Term.

                                       2
<PAGE>

  4. Tenant, at Tenant's sole cost and expense, shall have the right, without
any payment of additional rent, to install an emergency generator ("Generator")
and uninterrupted battery power source (the "Battery Source") (collectively the
Generator and Battery Source are referred to as the "Backup System") and
related equipment connecting such Backup System to the Premises (the "Related
Equipment").  The Generator shall be located at an exterior site and the
Battery Source shall be located within the Premises, with the exact locations
and space used being designated by Landlord (subject to the reasonable approval
of Tenant) following Landlord's receipt of specifications for such systems.  The
availability of The Backup System and Related Equipment shall be subject to the
following provisions:

     A.   The specifications and types of Generator and Battery Source
(including fuel source) and Related Equipment, and any alterations thereto,
shall be subject to the prior approval of Landlord, which approval shall not be
unreasonably withheld, conditioned or delayed. Landlord shall have the right to
require screening of the Generator and containment of the Battery Source. Upon
at least 24 hours' prior notice from Landlord (or in the event of an emergency,
such reasonable prior notice as necessary to give Tenant notice and safeguard
the Building and tenants therein), Tenant shall cease using the Generator or
Battery Source if Landlord has reason to believe that: (a) it is determined that
such installation or use materially interferes with the operation of machinery
and apparatus of the Building, such as the elevators; or (b) the installation
and use constitute a nuisance or hazard to the public or to the occupants of the
Building; or (c) the use of such Backup System or Related Equipment materially
interferes with the use of any tenant's equipment or data processing machines in
the Building or in other buildings in the Building Complex. Tenant shall have a
right to resume using the Backup System and Related Equipment if an independent
engineer selected by Tenant confirms in writing to Landlord that Backup System
and Related Equipment is not creating the alleged problems and provided that
Tenant indemnifies Landlord against claims arising from resumed operation.
Landlord may terminate Tenant's rights under this Paragraph upon at least 30
days' prior notice to Tenant if (a) it is determined that such installation or
use materially interferes with the operation of machinery and apparatus of the
Building, such as the elevators, and such interference is reasonably confirmed
in writing in good faith by an independent engineer selected by Landlord and,
based on the determination of such engineer, there is no other location in the
Building Complex (outside of tenants' premises including the Premises) where
Tenant's Backup System can be relocated to where this interference will no
longer occur; or (b) it is found by public authority having jurisdiction over
the Building that the installation and use constitute a nuisance or hazard to
the public or to the occupants of the Building and Tenant is unable to make
modifications to the Backup System that satisfy the public authority's findings;
or (c) the use of such Backup System or Related Equipment materially interferes
with the use of any tenant's equipment or data processing machines in the
Building or in other buildings in the Building Complex, and such interference is
reasonably confirmed in writing in good faith by an independent engineer
selected by Landlord, and there is no other location in the Building Complex
outside tenants' premises where Tenant's Backup System can be relocated to where
this interference will no longer occur; or (d) this Lease expires or is
terminated.

     B.   Upon expiration or earlier termination, Tenant will, at its sole cost
and expense, remove and retain the Backup System and the Related Equipment and
return the Building to the condition existing prior to such installation,
reasonable wear and tear and damage due to casualty excepted. Tenant will have
reasonable access to the Backup System and Related Equipment in order to be able
to keep and maintain the Backup System and the Related Equipment in good
condition and repair, at its sole expense, in a manner that does not conflict or
interfere with the use of other facilities installed in the Building. Further,
Tenant will not damage or permit damage to the Building in conjunction with the
Backup System and the Related Equipment.  The Backup System and Related
Equipment will be of types and frequencies that do not cause interference with
other equipment or operations in the Building or surrounding areas to the extent
such interference is unacceptable to Landlord, in Landlord's reasonable
determination.

     C.   Tenant will, at Tenant's sole cost and expense, comply with all
applicable laws, rules, regulations, statutes, ordinances or other requirements
of any kind or nature of any municipal, state and federal governmental or quasi-
governmental authority or the requirements of Landlord's insurance underwriters
relating to the installation, maintenance, height, location, use, operation, and
removal of the Backup System and Related Equipment and indemnify Landlord
against any loss, cost, or expense incurred resulting from the installation,
maintenance, operation, or removal of the Backup System and Related Equipment.
Landlord and Tenant agree to cooperate reasonably, at Tenant's cost, to seek to
obtain the approval of the Backup System from the applicable authorities.
Landlord makes no representation that applicable laws, ordinances or regulations
permit the installation or operation of the Backup System or Related Equipment
or that the design limitations of the site or Building will permit installation
and operation of the Backup System and Related Equipment specified by Tenant.
The insurance required to be carried by Tenant under Section 16.2 of the Lease
shall provide coverage with respect to the ownership, operation and use of the
Backup System and the Related Equipment.  Landlord has no responsibility or
liability for damage to the Backup System or the Related Equipment.

     D.   Landlord shall have the right to relocate the Backup System or Related
Equipment, or portions thereof, upon no less than 30 days' prior notice to other
areas at Landlord's cost, provided that such location permits substantially the
same operation of such equipment as was the case prior to such relocation.

                                       3
<PAGE>

  5. Notwithstanding anything to the contrary set forth in Exhibit D, Landlord
grants to Tenant a license for the term of the Lease without the payment of any
additional rent, for the purpose of installing, maintaining and operating on a
portion of the roof of the Building ("Roof"), the actual location to be
designated by Landlord, in Landlord's reasonable discretion ("Roof Space"), (1)
chillers and related equipment to connect the chillers to service equipment in
the Premises (collectively, "Chillers"), (2) non-penetrating
microwave/satellite dishes, not to exceed one meter in diameter and other
similar future types of telecommunications devices which may be a variant (the
"Dishes"), and (3) equipment, conduits, cables and materials to be located on
the Roof Space or in other parts of the Building serving the Chillers (such
equipment, conduits, cables, and materials collectively referred to herein as
the "Related Equipment") or  the Dishes (such equipment, conduits, cables,
materials, and Dishes collectively referred to herein as the "Communications
Equipment") in accordance with the terms of this Section.  All costs and
expenses related to installation (including costs of acquiring any required
permits therefor), maintenance, operation and removal of the Chillers, Related
Equipment, and Communications Equipment shall be borne by Tenant but Tenant
shall not pay any additional fee for use of the Chillers, Related Equipment, and
Communications Equipment under this Lease.  The plans and specifications for the
Chillers, Related Equipment, and Communications Equipment shall be subject to
approval by Landlord (which approval shall not be unreasonably withheld) and
approval under Applicable Laws and the Declaration.  The Chillers, Related
Equipment, and Communications Equipment shall be located within an appropriately
screened area.

     A.   Tenant will not use the Roof for any purpose other than operation of
the Chillers, Related Equipment, and Communications Equipment for Tenant's
business operations and Tenant shall not have any right to license or otherwise
provide use of the Chillers, Related Equipment, and Communications Equipment to
others except in connection with Collocation Services or to Permitted
Transferees or approved subtenants or assignees.  Tenant shall install access
pavers on the Roof at Tenant's sole cost and expense (if required beyond the
access pavers installed by Landlord as shown on Landlord's Drawings), and Tenant
and Tenant's agents, contractors, and employees shall have reasonable access to
the Chillers, Related Equipment, and Communications Equipment, and  agree to be
accompanied at all times by Landlord's designated representative when access to
the Roof Space, Chillers, Related Equipment, or Communications Equipment areas
is necessary for installation, repair and maintenance; Landlord will make such
representative available upon reasonable prior notice, and will provide Tenant
with the name and phone number of the Landlord's representative that is
available during other than Ordinary Business Hours.  Tenant will make every
reasonable effort to minimize the number of service calls made to the Roof
Space, Chillers, Related Equipment, or Communications Equipment areas and will
enter such only for required maintenance or in case of an emergency.  Tenant
must secure and maintain at all times all required approvals and permits of the
Federal Communications Commission and all other governmental bodies having
jurisdiction over its business, including its communications, operations and
facilities, provided that Landlord and Tenant agree to cooperate reasonably, at
Tenant's cost, to seek to obtain such approvals and permits from the applicable
governmental bodies.  Upon at least 24 hours' prior notice from Landlord (or in
the event of an emergency, such reasonable prior notice as necessary to give
Tenant notice and safeguard the Building and tenants therein), Tenant shall
cease using the Chillers, Related Equipment, and/or Communications Equipment if
Landlord has reason to believe that: (a) such installation or use materially
interferes with the operation of machinery and apparatus of the Building, such
as the elevators, or (b) the installation and use constitute a nuisance or
hazard to the public or to the occupants of the Building, or (c) the use of such
Communications Equipment interferes with the use of any tenant's equipment or
data processing machines in the Dulles Executive Plaza Complex or surrounding
areas that was installed prior to the installation of the Tenant's
Communications Equipment.  Tenant shall have a right to resume using the
Chillers, Related Equipment, and/or Communications Equipment (as applicable) if
an independent engineer selected by Tenant confirms in writing to Landlord that
such equipment is not creating the alleged problems and provided that Tenant
indemnifies Landlord against claims arising from resumed operation. Landlord may
terminate the license under this Section upon 30 days' prior notice to Tenant,
if: (a) it is determined that such installation or use materially interferes
with the operation of machinery and apparatus of the Building, such as the
elevators, and such interference is reasonably confirmed in writing in good
faith by an independent engineer selected by Landlord, and, based on the
determination of such engineer, there is no other location in the Building
Complex outside tenants' premises where the Chillers, Related Equipment, and/or
Communications Equipment (as applicable) can be relocated to where this
interference will no longer occur; or (b) it is found by public authority having
jurisdiction over the Building that the installation and use constitute a
nuisance or hazard to the public or to the occupants of the Building and Tenant
is unable to make modifications to the applicable equipment that satisfy the
public authority's findings; or (c) the use of such Communications Equipment
interferes with the use of any tenant's equipment or data processing machines in
the Dulles Executive Plaza Complex or surrounding areas that was installed prior
to the installation of the Tenant's Communications Equipment, and such
interference is reasonably confirmed in writing in good faith by an independent
engineer selected by Landlord, and there is no other location in the Building
Complex outside tenants' premises where Tenant's Communications Equipment can be
relocated to where this interference will no longer occur; or (d) this Lease
expires or is terminated.

     B.   Upon expiration or earlier termination, Tenant will, at its sole cost
and expense, remove the Chillers, Related Equipment, and Communications
Equipment and return the Roof Space to the condition existing prior to such

                                       4
<PAGE>

installation. Tenant will keep and maintain the Chillers, Related Equipment, and
Communications Equipment in good condition and repair, at its sole expense, in a
manner that does not conflict or interfere with the use of other facilities
installed in the Building or on the Roof.  Further, Tenant will not damage or
permit damage to the Roof or the Building in conjunction with the Chillers,
Related Equipment, and Communications Equipment.  The Communications Equipment
will be of types and frequencies that do not cause interference with other
equipment or operations in the Building, the Dulles Executive Plaza Complex, or
surrounding areas that was installed prior to the installation of the Tenant's
Communications Equipment.

     C.   All transmitters must be equipped with any transmitter isolator device
necessary to minimize spurious radiation.  If the Communications Equipment
causes interference, Tenant will take all commercially reasonable steps
necessary to eliminate the interference. Notwithstanding anything to the
contrary set forth in the default section of the Lease, if the interference is
not eliminated within 8 hours after Tenant receives Landlords notice thereof,
Tenant will be liable for all of Landlord's actual damages resulting therefrom
and will temporarily disconnect and shut down the Dishes (except for
intermittent operation for the purpose of correcting the interference) until the
interference is eliminated. If Tenant fails to cease operations at the request
of Landlord, Landlord will be entitled to injunctive relief and the cost of
obtaining such relief will be paid by Tenant. Landlord makes no warranty that
the Roof Space is suitable for the Dishes  or that it will perform according to
Tenant's requirements.

     D.   Landlord and its agents, employees, contractors or anyone else
permitted by Landlord to be on the Roof may from time to time repair, replace,
maintain, or install additional improvements or fixtures on the Roof.  Landlord
may permit other licensees to install other rooftop equipment, provided that
such equipment (i) does not result in blockage of the line of sight approved for
Tenant's initial installation of its Communications Equipment or relocation
thereof pursuant to Paragraph 6(A) above, and (ii) does not interfere with the
ability of Tenant's Communications Equipment to perform properly as reasonably
determined in writing in good faith by an independent engineer selected by
Tenant.  Tenant will cooperate in any repair, replacement, maintenance and
installation as reasonably required by Landlord from time to time.

     E.   Tenant will, at Tenant's sole cost and expense, comply with all
Applicable Laws, or the requirements of Landlord's insurance underwriters
relating to the installation, maintenance, height, location, use, operation, and
removal of said Chillers, Related Equipment, and Communications Equipment and
indemnify Landlord against any loss, cost, or expense incurred resulting from
the installation, maintenance, operation, or removal of said Chillers, Related
Equipment, and Communications Equipment.  Landlord makes no representation that
Applicable Laws permit the installation or operation of the Chillers, Related
Equipment, and Communications Equipment or that the design limitations of the
site or Building will permit installation and operation of the Chillers, Related
Equipment, and Communications Equipment.

     F.   The insurance required to be carried by Tenant under Section 16.2
shall provide coverage with respect to the ownership, operation and use of the
Chillers, Related Equipment, and Communications Equipment.  Landlord has no
responsibility or liability for damage to the Chillers, Related Equipment, and
Communications Equipment.

  6. Tenant shall provide to Landlord, at the time of execution hereof by
Tenant, a clean, unconditional, irrevocable letter of credit from a lending
institution reasonably acceptable to Landlord (it being agreed that First Union
National Bank located at 8739 Research Drive, Charlotte, NC 28262, is an
acceptable lending institution) in the form attached hereto as Exhibit G (the
"Letter of Credit ") to ensure the performance of Tenant's obligations under
this Lease on the following terms and conditions:

     A.    It is understood and agreed that the Letter of Credit, or a renewal
or substitute therefor approved by Landlord, shall be kept in effect from the
date of execution of this Lease through the last day of the expiration date of
the Initial Term (the "LC Termination Date").  The initial Letter of Credit
shall be in the amount of $7,600,000.00 (the "LC Maximum"). Tenant shall have a
right to provide a substitute or amended letter of credit based on the following
reductions in the LC Maximum as applicable under this paragraph. On the
commencement of the 61st full calendar month following the Commencement Date, if
an Event of Default has not occurred and is still continuing (or has not been
cured to the extent  permitted under the Lease) as of the date of the reduction,
the LC Maximum shall be reduced by $1,436,000.00 (resulting in the Letter of
Credit in the amount of $6,164,000.00); on the commencement of the 73rd full
calendar month following the Commencement Date if an Event of Default has not
occurred and is still continuing (or has not been cured to the extent  permitted
under the Lease) as of the date of the reduction, the LC Maximum shall be
reduced by an additional $1,436,000.00 (resulting in a Letter of Credit in the
amount of $4,728,000.00); on the commencement of the 85th  full calendar month
following the Commencement Date if an Event of Default has not occurred and is
still continuing (or has not been cured to the extent  permitted under the
Lease) as of the date of the reduction, the LC Maximum shall be reduced by an
additional $1,436,000.00 (resulting in a Letter of Credit in the amount of
$3,292,000.00); on the commencement of the 96th full calendar month following
the Commencement Date if an Event of Default has not occurred and is still
continuing (or has not been cured to the extent  permitted under the Lease) as
of the date of the reduction, the LC Maximum shall be reduced by an additional
$1,436,000.00 (resulting in a Letter of Credit in the amount of $1,856,000); and
on the commencement of the 108th

                                       5
<PAGE>

full calendar month following the Commencement Date if an Event of Default has
not occurred and is still continuing (or has not been cured to the extent
permitted under the Lease) as of the date of the reduction, the LC Maximum shall
be reduced by an additional $1,336,000.00 (resulting in a Letter of Credit in
the amount of $520,000.00). Additionally, the foregoing reductions shall not be
applicable if and so long as Tenant is the subject of a proceeding under any
provision of federal or state law relating to insolvency, bankruptcy, or
reorganization at the time. If the Letter of Credit would otherwise expire prior
to the LC Termination Date, Tenant shall present Landlord with an extension or
renewal of the initial Letter of Credit, or a substitute Letter of Credit in the
same form as Exhibit G, no later than 30 days prior to the expiration date of
such initial Letter of Credit, from a lending institution subject to Landlord's
reasonable approval; such extension, renewal or substitute Letter of Credit
shall be effective no later than 10 days prior to the expiration of the initial
Letter of Credit and shall continue in effect for not less than the period
ending with the LC Termination Date and shall be in the amount provided above,
reflecting the adjusted LC Maximum as applicable. Tenant agrees that in an Event
of Default by Tenant, Landlord shall have a right to present the Letter of
Credit (or the renewal, extension or substitute) for payment one or more times
up to the entire amount of the then applicable LC Maximum, with amounts received
to be applied by Landlord in accordance with subparagraph B below. Any failure
of Tenant to timely provide Landlord with an extension, renewal or substitute
Letter of Credit, as required hereunder, shall be automatically and without
notice deemed an Event of Default under the Lease and Landlord shall have a
right to present the Letter of Credit in accordance with the foregoing
provision. If the Letter of Credit has not been presented for payment in
accordance with this Section on or before the LC Termination Date, Landlord
shall return the Letter of Credit to the issuer within 30 days after the LC
Termination Date. The Letter of Credit shall be transferable and assignable to
any person or entity who or which is the successor or assignee of Landlord's
interest under the Lease, including an assignment as security for a loan to
Landlord, and Tenant shall cooperate in effecting any such transfer or
assignment from time to time, including obtaining a substitute Letter of Credit
(at Tenant's cost and expense), if the existing Letter of Credit is not capable
of further transfer or assignment. Landlord shall give notice to Tenant of
transfer of Landlord's interest resulting in transfer of the Letter of Credit.
Landlord shall deliver the then-current effective Letter of Credit to the issuer
marked for cancellation upon receipt of any conforming renewal or substitute
Letter of Credit provided in accordance with this Paragraph and cooperate with
the issuing bank to effect the release of such then-current effective Letter of
Credit as soon as the renewal or substitute Letter of Credit is in effect
pursuant to its terms. Tenant agrees to pay all fees charged by the lending
institution issuing the Letter of Credit (or any reduction, renewal, extension,
or substitute therefor).

     B.   If an Event of Default occurs or this Lease is terminated pursuant to
Section 20, Landlord may use, apply or retain all or any portion of the amounts
received under the Letter of Credit, if any, for the payment of any rent or
other charge in default or for the payment of any other sum to which Landlord
may become obligated by reason of Tenant's default, or to compensate Landlord
for any loss or damage which Landlord may suffer thereby in accordance with
Section 20 of the Lease. Any amounts received under the Letter of Credit that
are not applied against loss, damage or other amounts under Section 20 of the
Lease shall be returned to the issuer.

     C.   Upon the expiration or earlier termination of the Lease (without
regard to the reason(s) for such termination), Landlord shall have the right to
present the Letter of Credit for payment of $100,000.00 attributable to
alterations and improvements to the ceiling of the Premises (the "Ceiling
Reimbursement").  As described in greater detail in the Work Letter, Landlord
has permitted Tenant to utilize an unconventional ceiling design and the parties
have jointly determined that the Ceiling Reimbursement will adequately
compensate Landlord for the cost of restoring the ceiling to a more traditional
form.  Landlord's right to the Ceiling Reimbursement is not contingent on the
occurrence of an Event of Default, and should Landlord ever be entitled to any
damages pursuant to Section 20 of the Lease, such damages shall be in addition
to and not inclusive of the Ceiling Reimbursement.  Notwithstanding anything
contained herein to the contrary, in the event that Tenant exercises its right
to the Option Term and such Option Term expires in accordance with its terms,
upon such expiration, Landlord shall no longer be entitled to the Ceiling
Reimbursement.

  7. Landlord shall use reasonable efforts to lease approximately 1,000 - 1,500
square feet of space situated on the ground floor of the Building or in the
proposed building to be known Dulles Executive Plaza II (if constructed and
leased by Landlord) to a delicatessen or similar food service operation.
Landlord's failure to lease space for such use shall not constitute a default by
Landlord under this Lease or entitle Tenant to exercise remedies for a default
by Landlord.

  8. Subject to the design capacity of the Building Improvements, Tenant shall
have the right to construct conduits, install cabling through the Building's
core and raceways, install equipment and other related telecommunications
facilities for Tenant's Communications Equipment (as defined above), and access
the Building at those points reasonably designated by Landlord for
telecommunications conduits.  Other than installation of cabling in existing
conduits, Landlord's approval shall be required for installation of such
equipment outside the Premises.  If Tenant's use exceeds its proportionate share
of the available conduits leading to the Building (based on its Pro Rata Share),
Tenant shall be obligated to install additional conduit for such excess at
Tenant's cost.

                                       6
<PAGE>

  IN WITNESS WHEREOF, the parties hereto execute this Addendum.

<TABLE>
<S>                                                        <C>
LIFEMINDERS.COM, INC., a Delaware corporation               DTC ASSOCIATES, LLC, a Virginia limited liability company

By:                                                        By:

Print Name:                                                                   Authorized Signatory

Print Title:
                                                                                   "Landlord"
ATTEST:

By:

Print Name:

Print Title:

                        "Tenant"
</TABLE>

                                       7
<PAGE>

                              EXHIBIT A TO LEASE

                                 THE PREMISES
                                 ------------

                                       1
<PAGE>

                              EXHIBIT B TO LEASE

                                 REAL PROPERTY
                                 -------------

Parcel 4N1, Dulles Technology Center, Hunter Mill District, Fairfax County,
                  Virginia as the same is shown on the Plat entitled "Division
                  Plat of a Portion of Parcel C DULLES TECHNOLOGY CENTER VENTURE
                  D.B. 8206 PG. 942 and Parcel B DULLES TECHNOLOGY CENTER
                  VENTURE D.B. 6910 PG. 911" which Plat is attached to the Deed
                  of Consolidation and Resubdivision recorded in Deed Book 11078
                  at Page 130 among the Land Records of Fairfax County,
                  Virginia.

                                       1
<PAGE>

  EXHIBIT C TO LEASE

                              OPERATING EXPENSES
                              ------------------

     6.1  Definitions.  The additional terms below have the following meanings
          -----------
in this Lease:

          (1) "Base Operating Expenses" means an amount equal to the Operating
Expenses for the calendar year identified as the Base Year in Section 1.5, as
determined by Landlord in accordance with this Exhibit C. Tenant acknowledges
Landlord has not made any representations or warranties that the Base Operating
Expenses will equal any specified amounts (any estimates provided by Landlord
are non-binding estimates only).

          (2) "Landlord's Accountants" means that individual or firm employed
by Landlord from time to time to keep the books and records for the Building
Complex, and/or to prepare the federal and state income tax returns for Landlord
with respect to the Building Complex, which books and records shall be certified
to by a representative of Landlord. All determinations made hereunder shall be
made by Landlord's Accountants unless otherwise stated.

          (3) "Rentable Area" means 189,701 rentable square feet of space.  If
there is a significant change in the aggregate Rentable Area as a result of an
addition, partial destruction, modification to building design, or similar cause
which causes a reduction or increase in the Rentable Area on a permanent basis
or, if Landlord remeasures the Building (excluding roof and garage space) and a
change in Rentable Area occurs, Landlord's Accountants shall make such
adjustments in the computations as are necessary to provide for such change.

          (4) "Tenant's Pro Rata Share" means the percentage set forth in
Section 1.5.  If Tenant, at any time during the Term, leases additional space in
the Building or if the Rentable Area is adjusted, Tenant's Pro Rata Share shall
be recomputed by dividing the total rentable square footage of space then leased
by Tenant (including any additional space) by the Rentable Area and the
resulting figure shall become Tenant's Pro Rata Share.

          (5) "Operating Expense Year" means each calendar year during the
Term, except that the first Operating Expense Year begins on the Commencement
Date and ends on December 31 of such year and the last Operating Expense Year
begins on January 1 of the calendar year in which this Lease expires or is
terminated and ends on the date of such expiration or termination.  If an
Operating Expense Year is less than twelve (12) months, Operating Expenses for
such year shall be prorated.

          (6) "Operating Expenses" means all commercially reasonable or
customary operating expenses of any kind or nature which are in Landlord's
reasonable judgment necessary, appropriate, or customarily incurred in
connection with the operation and maintenance of the Building Complex (to the
extent such expenses are reasonably allocated to the Building if applicable
under the following provisions) and are determined in accordance with generally
accepted accounting principles consistently applied, as applicable and with
adjustments as appropriate for the real estate industry ("GAAP").  Operating
Expenses include:

              (a) All real property taxes and assessments levied against the
Building Complex by any governmental or quasi-governmental authority or under
any covenants, declarations, easements or restrictions, including taxes,
assessments, surcharges, or service or other fees of a nature not presently in
effect which are hereafter levied on the Building Complex as a result of the
use, ownership or operation of the Building Complex or for any other reason, to
the extent such taxes are in lieu of or in addition to any current real estate
taxes and assessments as a substitution for otherwise increasing real estate
taxes and assessments.  However, any taxes which are levied on the rent of the
Building Complex will be determined as if the Building Complex were Landlord's
only real property.  In addition, if the Building, the parking facilities or the
Property are subject to any provision for tax abatement or are not fully
assessed during the Base Year as a result of the incomplete status of the
Building Complex, the Base Operating Expenses for determining increases in Real
Estate Taxes shall be adjusted to reflect the estimated taxes that would have
been applicable for a fully completed Building Complex.  In no event do taxes
and assessments include (i) federal or state income taxes, (ii) rental or other
charges or fees imposed upon Landlord in connection with the lease or use of any
vault space, (iii) gross receipts taxes, excess profits taxes, excise taxes,
franchise taxes, estate taxes, succession taxes and transfer taxes (except to
the extent such taxes are in substitution for or recharacterization or
replacement of Taxes as a substitution for otherwise increasing real estate
taxes and assessments), (iv) real estate taxes and other impositions on separate
tax lots, or (v) any interest or penalties arising by reason of the late payment
of Taxes levied or assessed on Landlord.  Expenses for tax consultants to
contest taxes or assessments are also included as Operating Expenses (all of the
foregoing are collectively referred to herein as "Taxes").  Taxes also include
special assessments, license taxes, business license fees, business license
taxes, and, to the extent not excluded above, commercial rental taxes, levies,
charges, or taxes, imposed by any authority against the Premises, Building
Complex or any legal or equitable interest of Landlord.  Special assessments are
deemed payable in such number of installments permitted by law, whether or not
actually so paid, and include any applicable interest on such installments.
Taxes (other than special assessments) are computed on an accrual basis based on
the year in which they are levied, even though not paid until the following
Operating Expense Year;

                                       1
<PAGE>

          (b) Costs of supplies, including costs of relamping and replacing
ballasts in all Building standard tenant lighting;

          (c) Costs of energy for the Building Complex, including costs of
propane, butane, natural gas, steam, electricity (exclusive of electricity
supplied to tenants' premises), solar energy and fuel oils, coal or any other
energy sources;

          (d) Costs of water and sanitary and storm drainage services;

          (e) Costs of janitorial and security services;

          (f) Costs of general maintenance, repairs, and replacements including
costs under HVAC and other mechanical maintenance contracts; and repairs and
replacements of equipment used in maintenance and repair work;

          (g) Costs of maintenance, repair and replacement of landscaping;

          (h) Insurance premiums for the Building Complex for insurance required
to be carried by Landlord under the terms of this Lease or  under any applicable
Mortgage or otherwise deemed appropriate by Landlord to the extent of types and
amounts customarily maintained by landlords of similar first class office
buildings in the Herndon-Dulles metropolitan area, including all-risk or multi-
peril coverage, together with loss of rent endorsement; the part of any claim
paid under the commercially reasonable deductible portion of any insurance
policy carried by Landlord; public liability insurance; and any other insurance
carried by Landlord on any component parts of the Building Complex;

          (i) All labor costs, including wages, costs of worker's compensation
insurance, payroll taxes, fringe benefits, including pension, profit-sharing and
health, and reasonable legal fees and other costs incurred in resolving any
labor dispute;

          (j) Professional building management fees (not to exceed 5% of gross
revenues, including base rents and additional rents, with respect to the
Building payable to Landlord during the applicable calendar year), costs and
expenses, including costs of office space and storage space required by
management for performance of its services;

          (k) Reasonable legal, accounting, inspection, and other consulting
fees (including fees for consultants for services designed to produce a
reduction in Operating Expenses or improve the operation, maintenance or state
of repair of the Building Complex) to the extent not included in the
professional building management fees;

          (l) Costs of capital improvements and structural repairs and
replacements to the Building Complex to conform to changes subsequent to the
date of issuance of the shell and core certificate of occupancy for the Building
in any Applicable Laws (herein "Required Capital Improvements"); and the costs
of any capital improvements and structural repairs and replacements designed
primarily to reduce Operating Expenses (herein "Cost Savings Improvements").
Expenditures for Required Capital Improvements and Cost Savings Improvements
will be amortized at a market rate of interest (not to exceed the prime rate
plus 2%) over the useful life of such capital improvement (as determined in
accordance with GAAP by Landlord's Accountants); however, the amortized amount
of any Cost Savings Improvement  in any year will be equal to the estimated
resulting reduction in Operating Expenses; and

          (m) Costs incurred for Landlord's Accountants including costs of any
experts and consultants engaged to assist in making the computations;

"Operating Expenses" do not include:
                        ---

              (i) Costs of work, including painting and decorating, which
Landlord performs for any tenant other than work of a kind and scope which
Landlord is obligated to furnish to all tenants whose leases contain a rental
adjustment provision similar to this one, including, without limitation, the
cost of preparing any space in the Building for occupancy by any tenant and/or
for altering, renovating, repainting, decorating, planning and designing spaces
for any tenant in the Building in connection with the renewal of its lease
and/or costs of preparing or renovating any vacant space for lease in the
Building (including permit, license and inspection fees);

                                       2
<PAGE>

                  (ii)    Costs of repairs or other work occasioned by fire,
windstorm or other insured casualty to the extent of insurance proceeds
received, provided, however, that with respect to the cost to repair damage,
Landlord may include in Operating Expenses the amount of a commercially
reasonable deductible applied to each such occurrence; provided, however, that
Landlord may only include such cost in Operating Expenses, if Landlord actually
makes such repair;

                  (iii)   Leasing commissions, advertising expenses, and other
costs incurred in leasing space in the Building;

                  (iv)    Costs of repairs or rebuilding necessitated by
condemnation;

                  (v)     Interest on borrowed money or debt amortization,
except as specifically set forth above, or any other charges paid by Landlord in
connection with any mortgages, deeds of trust or other financing encumbrances or
attorney's fees and disbursements, recording costs, mortgage recording taxes,
title insurance premiums, title closer's gratuity and other similar costs,
incurred in connection with any mortgage financing or refinancing or execution,
modification or extension of any ground lease; loan prepayment penalties,
premiums, fees or charges;

                  (vi)    Depreciation on the Building Complex;

                  (vii)   Rental payments (including percentage rent and any
increases in base rent) made under any ground lease;

                  (viii)  Salaries and all other compensation (including fringe
benefits and other direct and indirect personnel costs) of partners, officers
and executives above the grade of superintendent or building manager of Landlord
or the managing agent;

                  (ix)    The costs of repairs, replacements and alterations
for which and to the extent that Landlord is actually reimbursed therefor from
any source other than as a result of inclusion in Operating Expenses generally;

                  (x)     Fees, costs and expenses incurred by Landlord in
connection with or relating to claims against or disputes with tenants of the
Building or the negotiation or enforcement of leases with tenants or prospective
tenants, including, without limitation, legal fees and disbursements;

                  (xi)    Expenses for the correction of defects in Landlord's
initial construction of the Building, Project, or any part thereof, except that
conditions (not occasioned by construction defects) resulting from ordinary wear
and tear will not be deemed defects for the purpose of this category; the cost
of repair or replacement of any item covered by warranty;

                  (xii)   Costs and expenses incurred by Landlord for services
which are duplicative of any management fees paid by Landlord;

                  (xiii)  That portion of any Operating Expenses which is paid
to any entity affiliated with Landlord which is in excess of the amount which
would otherwise be paid to an entity which is not affiliated with Landlord for
the provision of the same service;

                  (xiv)   Sums paid by Landlord for any indemnity, damages,
fines, late charges, penalties or interest for any late payment;

                 (xv)     Costs attributable to any "tap fees" or one-time
lump sum sewer or water connection fees payable in connection with the
construction of the Building;

                  (xvi)   Rental for personal property leased to Landlord (e.g.,
furnishings in Landlord's Building management office) except for rent for
personal property leased to Landlord and used in the operation or maintenance of
the Building, the purchase price for which, if purchased, would be fully
includable in Operating Expenses in the year of purchase (e.g., rental for
equipment used in the fitness facility shall be included as an Operating
Expense);

                  (xvii)  Attorney's fees and disbursements, brokerage
commissions, transfer taxes, recording costs and taxes, title insurance
premiums, title closer's fees and gratuities and other similar costs incurred in
connection with the sale or transfer of an interest in Landlord or the Building;

                                       3
<PAGE>

                  (xviii)  Costs and expenses of administration and management
of partnership activities of Landlord; or

                  (xix)    Costs arising from the presence of hazardous
materials, substances, wastes, or asbestos-containing materials in or about or
below the Building, the Land, or the Project, including without limitation,
hazardous substances in the groundwater or soil (other than ordinary maintenance
costs, including changing filters, etc.), unless the materials, substances,
wastes or asbestos-containing materials were in or on the Property due to
Tenant's negligence or intentional acts;

                  (xx)     Capital expenditures as a result of Landlord's
failure to comply with laws or building codes in existence as of the issuance of
the building permit for the Building or capital expenditures not otherwise
expressly permitted under 6.1(l) above.

To the extent that employees, utilities or other services or costs are
attributable to the Building and other buildings on a common basis or are
provided for Common Areas, such Operating Expenses shall be reasonably prorated
by Landlord to reflect costs to be allocated hereunder to the Building.  If any
lease entered into by Landlord with any tenant in the Building is on a so-called
"net" basis, or provides for a separate basis of computation for any Operating
Expenses with respect to its leased premises, Landlord's Accountants may modify
the computation of Base Operating Expenses, Rentable Area, and Operating
Expenses for a particular Operating Expense Year to eliminate or modify any
expenses which are paid for in whole or in part by such tenant.  Specifically,
electricity to tenants' premises shall be excluded based on electricity to the
Premises being separately metered and paid for by Tenant.  If the Rentable Area
is not fully occupied during any particular Operating Expense Year (including
the Base Year), Landlord's Accountants shall adjust those Operating Expenses
which are affected by occupancy for the particular Operating Expense Year to
reflect 95% occupancy.  Furthermore, in making any computations contemplated
hereby, Landlord's Accountants may make such other modifications to the
computations as are required in their judgment to achieve the intention of the
parties hereto.

     6.2  Additional Payment.  If any increase occurs in Operating Expenses for
          ------------------
any Operating Expense Year during the Term, commencing with calendar year 2002,
in excess of the Base Operating Expenses, Tenant shall pay Landlord Tenant's Pro
Rata Share of the amount of such increase (less Estimated Payments, if any,
previously made by Tenant for such year).

     6.3  Estimated Payments.  During each Operating Expense Year beginning with
          ------------------
the first month of calendar year 2002 and continuing each month thereafter
throughout the Term, Tenant shall pay Landlord, at the same time as Base Rent is
paid, an amount equal to 1/12 of Landlord's estimate of Tenant's Pro Rata Share
of any projected increases in Operating Expenses for the particular Operating
Expense Year in excess of Base Operating Expenses ("Estimated Payment").

     6.4  Annual Adjustments.
          ------------------

          (1) Following the end of each Operating Expense Year, including the
first Operating Expense Year, Landlord shall submit to Tenant a statement
setting forth the exact amount of Tenant's Pro Rata Share of the increase, if
any, of the Operating Expenses for the Operating Expense Year just completed
over the Base Operating Expenses.  Beginning with the statement for the second
Operating Expense Year, each statement shall set forth the difference, if any,
between Tenant's actual Pro Rata Share of the increase in Operating Expenses for
the Operating Expense Year just completed and the estimated amount for such
Operating Expense Year.  Each statement shall also set forth the projected
increase, if any, in Operating Expenses for the new Operating Expense Year over
Base Operating Expenses and the corresponding increase or decrease in Tenant's
monthly Rent for such new Operating Expense Year above or below the Rent paid by
Tenant for the immediately preceding Operating Expense Year.

          (2) To the extent that Tenant's Pro Rata Share of the increase in
Operating Expenses for the period covered by a statement is different from the
Estimated Payment during the Operating Expense Year just completed, Tenant shall
pay Landlord the difference within 30 days following receipt by Tenant of the
statement or receive a credit against the next due Rent, as the case may be.
Until Tenant receives a statement, Tenant's Estimated Payment for the new
Operating Expense Year shall continue to be paid at the prior Estimated Payment,
but Tenant shall commence payment of Rent based on the new Estimated Payment
beginning on the first day of the month following the month in which Tenant
receives the statement.  Tenant shall also pay Landlord or deduct from the Rent,
as the case may be, on the date required for the first payment, as adjusted, the
difference, if any, between the Estimated Payment for the new Operating Expense
Year set forth in the statement and the Estimated Payment actually paid during
the new Operating Expense Year.  If, during any Operating Expense Year, there is
a change in the information on which Tenant is then making its Estimated
Payments so that the prior estimate is no longer accurate, Landlord may revise
the estimate and there shall be such adjustments made in the monthly Rent on the
first day of the month following notice to Tenant as shall be necessary by
either increasing or decreasing, as the case may be, the amount of monthly Rent
then being paid by Tenant for the balance of the Operating Expense Year.

                                       4
<PAGE>

     6.5  Miscellaneous.  In no event will any decrease in Rent pursuant to any
          -------------
provision hereof result in a reduction of Rent below the Base Rent.  Delay by
Landlord in submitting any statement for any Operating Expense Year does not
affect the provisions of this Section or constitute a waiver of Landlord's
rights for such Operating Expense Year or any subsequent Operating Expense
Years.

     6.6  Dispute.  If Tenant disputes an adjustment submitted by Landlord or a
          -------
proposed increase or decrease in the Estimated Payment, Tenant shall give
Landlord notice of such dispute within 180 days after Tenant's receipt of the
adjustment.  If Tenant does not give Landlord timely notice, Tenant waives its
right to dispute the particular adjustment.  If Tenant timely objects, Tenant
may engage its own certified public accountants hired on a noncontingency basis
and providing a full range of accounting services or which is a national or
regional full-service accounting firm that is hired by Tenant on a contingency
or noncontingency basis ("Tenant's Accountants") to verify the accuracy of the
statement complained of or the reasonableness of the estimated increase or
decrease and to audit Landlord's books and records pertaining to Operating
Expenses.  Landlord shall cooperate (without charge) in permitting any such
audit, provided that such audit shall be conducted during Ordinary Business
Hours during weekdays, upon reasonable prior notice to Landlord and scheduling
of such audit.  The person conducting the examination on behalf of Tenant shall
enter into a confidentiality agreement satisfactory to Landlord.  If Tenant's
Accountants determine that an error has been made, Landlord's Accountants and
Tenant's Accountants shall endeavor to agree upon the matter, failing which such
matter shall be submitted to an independent certified public accountant selected
by Landlord, with Tenant's reasonable approval, for a determination which will
be conclusive and binding upon Landlord and Tenant.  All costs incurred by
Tenant for Tenant's Accountants shall be paid for by Tenant unless Tenant's
Accountants disclose an error, acknowledged by Landlord's Accountants (or found
to have occurred through the above independent determination), of more than 5%
in the computation of the total amount of Operating Expenses, in which event
Landlord shall pay the reasonable costs incurred by Tenant to obtain such audit,
provided that the amount of such reimbursement shall be based on a reasonable
hourly rate and reasonable out-of-pocket expenses and not any contingency fee.
Notwithstanding the pendency of any dispute, Tenant shall continue to pay
Landlord the amount of the Estimated Payment or adjustment determined by
Landlord's Accountants until the adjustment has been determined to be incorrect.
If it is determined that any portion of the Operating Expenses were not properly
chargeable to Tenant, then Landlord shall promptly credit or refund the
appropriate sum to Tenant.

     6.7  Tax Contest.  Notwithstanding anything in the Lease or this Exhibit to
          -----------
the contrary, if Landlord appeals Taxes and obtains a refund for any calendar
year in which Tenant paid increases in Operating Expenses pursuant to this
Exhibit, then Landlord shall promptly pay to Tenant Tenant's Pro Rata Share of
such refund as reasonably calculated by Landlord (after deducting the reasonable
expenses incurred by Landlord in obtaining such refund to the extent not
otherwise included in Taxes); provided, however, in no event shall the amount of
Tenant's Pro Rata Share of such refund be greater than the total amounts paid to
Landlord by Tenant pursuant to this Exhibit on account of increases in Operating
Expenses with respect to the calendar year to which such statement relates.  If
Landlord determines not to challenge or appeal such assessment (or, having
undertaken to appeal or challenge such an assessment, does not pursue the appeal
or challenge with due diligence and continuity), Landlord agrees that Tenant may
appeal or challenge such assessment in Landlord's place and stead and that
Landlord will join in and cooperate with Tenant in prosecuting such appeal or
challenge (subject to Landlord's reasonable approval of documents submitted in
such matter); provided, however, that such appeal or challenge shall be
undertaken at Tenant's sole cost and at no expense to Landlord (except that, if
Tenant's appeal or challenge is successful, then Tenant may recover its
reasonable costs out of the refund or reduction of Taxes achieved by Tenant
prior to allocating such reduction to the tenants of the Building).

                                       5
<PAGE>

                              EXHIBIT D TO LEASE

                            COMMENCEMENT CERTIFICATE
                            ------------------------

                            __________________, 2000

LIFEMINDERS.COM, INC.
__________________________
__________________________
__________________________
__________________________

RE:  Lease dated as of the  (the "Lease"), by and between DTC ASSOCIATES, LLC,
     a Virginia limited liability company, as Landlord, and LIFEMINDERS.COM,
     INC., a Delaware corporation, as Tenant

Dear Tenant:

  With regard to the referenced Lease, Landlord and Tenant acknowledge the
following (initially capitalized words not otherwise defined have the same
meaning set forth in the Lease):

  1. In accordance with Section 5 of the Lease, the Commencement Date is 12:01
a.m., __________________ and the Expiration Date is 12:00 midnight,
___________________.

  Please acknowledge the foregoing by having an authorized officer sign in the
space provided below and return to our office.  This document may be executed in
counterparts, each of which shall constitute the original.  Facsimile signatures
shall be binding as original signatures.

                                          DTC ASSOCIATES, LLC, a Virginia
                                          limited liability company

                                          By:
                                                     Authorized Signatory

                                                          "Landlord"

ACKNOWLEDGED AND AGREED this _____ day of
_______________________:

LIFEMINDERS.COM, INC., a Delaware corporation

By:
Print Name:
Print Title:

ATTEST:

By:
Print Name:
Print Title:

                "Tenant"

                                       1
<PAGE>

                              EXHIBIT E TO LEASE

                             RULES AND REGULATIONS
                             ---------------------

  1. Except as otherwise expressly set forth in the Lease, no sign, placard,
picture, advertisement, name or notice shall be installed or displayed on any
part of the outside or inside of the Building without the prior written consent
of the Landlord, which shall not be unreasonably withheld, conditioned, or
delayed.  Landlord shall have the right to remove, at Tenant's expense and
without notice, any sign installed or displayed in violation of this rule. All
approved signs or lettering on doors and walls shall be printed, painted,
affixed or inscribed at the expense of Tenant by a person or vendor approved by
Landlord. In addition, Landlord reserves the right to change from time to time
the format of the signs or lettering and to require previously approved signs or
lettering to be appropriately altered.

  2. The coverings for all windows in each tenant's premises shall be lowered
and closed as reasonably required because of the position of the sun, during the
operation of the Building's air-conditioning system to heat, cool or ventilate
such Premises.  All tenants with premises visible from one of the lobbies, or
any other public portion of the Building, shall furnish and maintain its
premises in a first-class manner, utilizing furnishings and other decorations
commensurate in quality and style with the furnishings and decor in the public
portions of the Building. If Landlord objects in writing to any curtains,
blinds, shades or screens attached to or hung in or used in connection with any
window or door of the Premises, Tenant shall immediately discontinue such use.
No awning shall be permitted on any part of the Premises. Tenant shall not place
anything or allow anything to be placed against or near any glass partitions or
doors or windows which may appear unsightly, in the reasonable opinion of
Landlord, from outside the Premises.

  3. Tenant shall not obstruct any sidewalks, halls, passages, exits, entrances,
elevators, escalators or stairways of the Building. The halls, passages, exits,
entrances, shopping malls, elevators, escalators and stairways are not for the
general public.

  4. The directory of the Building will be provided exclusively for the display
or the name and location of tenants, subtenants and assignees only and Landlord
reserves the right to exclude any other names therefrom.

  5. Except as otherwise expressly provided in the Lease, unless otherwise
approved by Landlord, all cleaning and janitorial services for the Building and
the Premises shall be provided exclusively through Landlord. Tenant shall not
cause any unnecessary labor by carelessness or indifference to the good order
and cleanliness of the Premises. Landlord shall not in any way be responsible to
any Tenant for any loss to property on the Premises, however occurring, or for
any damage to any Tenant's property by the janitor or any other employee or any
other person.

  6. Landlord will furnish Tenant free of charge with two keys or other access
devices to each locking access door in the Premises. Except as otherwise
expressly provided in this Lease, Landlord may make a reasonable charge for any
access devices, and Tenant shall not make or have made additional access
devices, and Tenant shall not alter any lock or install a new or additional lock
or bolt on any door of its Premises. Tenant, upon the termination of its
tenancy, shall deliver to Landlord the access devices of all doors which have
been furnished to Tenant, and in the event of loss of any access devices so
furnished, shall pay Landlord therefor.  Tenant's key system shall be separate
from the rest of the Building.

  7. It Tenant requires telegraphic, telephonic, burglar alarm or similar
services, it shall first obtain, and comply with, Landlord's reasonable
instructions in their installation. Landlord, or its agents, will direct the
electricians as to where and how the wires may be introduced, and without such
direction, no boring or cutting for wires will be permitted. Any such
installation and connection shall be made at Tenant's expense.  Except as
otherwise expressly provided in the Lease, Tenant shall be responsible for
removing, at Tenant's expense, prior to the end of the Term, all telephone,
data, cable television, or other cabling, installed for Tenant's benefit,
extending from the Premises to the telephone closet located on that floor.

  8. No equipment, materials, furniture, packages, supplies, merchandise or
other property that requires larger transport devices than hand trucks for
movement will be received in the Building or carried in the elevators except
between such hours and in such elevators as may be designated by Landlord.  The
persons employed to move furnishings, fixtures and equipment in and out of the
Building shall be properly licensed if required by law. Tenant must make
arrangements in advance with Landlord for moving large quantities of furniture
and equipment into or out of the Building.

  9. Tenant shall not place a load upon any floor which exceeds the load
per square foot which such floor was designed to carry and which is allowed by
law. Landlord shall have the right to prescribe the weight, size and position to
all equipment, materials, furniture or other property brought into the Building.
Heavy objects shall stand on such platforms as determined by Landlord to be
necessary to properly distribute such weight. Business machines and mechanical
equipment belonging to Tenant which

                                       1
<PAGE>

cause noise or vibration which may be transmitted to the structure of the
Building or to any space in the Building to such a degree as to be objectionable
to Landlord or to any tenants shall be placed and maintained by Tenant, at
Tenant's expense, on vibration eliminators or other devices sufficient to
eliminate noise or vibration. Landlord will not be responsible for loss of or
damage to, any such equipment or other property from any cause, and all damage
done to the Building by maintaining or moving such equipment or other property
shall be repaired at the expense of Tenant.

     10.   No Tenant shall tamper with or attempt to adjust temperature control
thermostats in its Premises other than temperature control thermostats for any
separate HVAC units for Tenant's computer facilities.  Tenant will be billed for
damage to thermostats due to tampering.  Tenant shall not use any method of
heating or air conditioning other than that supplied by Landlord. Tenant shall
not waste electricity, water or air conditioning.  Tenant shall keep corridor
doors closed.

     11.  Landlord reserves the right to exclude from the Building outside
Ordinary Business Hours any person unless that person is known to the person or
employee in charge of the Building and has an access device such as a key, entry
card, combination code, pass or is properly identified. Tenant shall be
responsible for all persons for whom it requests passes and, subject to the
provisions of the Lease, shall be liable to Landlord for all acts of such
persons. Any person whose presence in the Building at any time shall, in the
reasonable judgment of the Landlord, be prejudicial to the safety, character,
reputation and interests of the Building or its Tenants may be denied access to
the Building or may be ejected therefrom, including any person who in the
judgment of Landlord is intoxicated or under the influence of liquor or illicit
drugs or who shall in any manner do any act in violation of these Rules and
Regulations. In case of public excitement or other commotion, the Landlord may
prevent all access to the Building during the continuance of the same, by
closing the doors or otherwise, for the safety and protection of tenants, the
Building, and property in the Building. The Landlord may require any person
leaving the Building with a package or other object to exhibit authorization
from the Tenant of the premises from which the package or object is removed, but
the establishment and enforcement of such requirement shall not impose any
responsibility on the Landlord to protect any Tenant against the removal of
property from its premises. The Landlord shall in no way be liable to any Tenant
for damages or loss arising from the admission, exclusion or ejection of any
person to or from Tenant's Premises or the Building under the provisions of this
rule.

     12.  Tenant shall endeavor to close and lock the doors to the outside of
its Premises and entirely shut off all water faucets or other water apparatus
and electricity, gas or air outlets before Tenant and its employees leave the
Premises. Tenant shall be responsible for any damage or injuries sustained by
other tenants or occupants of the Building or by Landlord for noncompliance with
this rule.

     13.  The toilet rooms, toilets, urinals, wash bowls and other apparatus
shall not be used for any purpose other than that for which they were
constructed, no foreign substance or any kind whatsoever shall be thrown into
any of them, and the expense of any breakage, stoppage or damage resulting from
the violation of this rule shall be borne by the Tenant who, or whose employees
or invitees, shall have caused it.

     14.  Except as otherwise expressly provided in the Lease, Tenant shall not
install any radio or television antenna, satellite dish, loudspeaker or other
device on the roof or exterior walls of the Building. Tenant shall not interfere
with radio or television broadcasting or reception from or in the Building or
elsewhere.

     15.  Except for the installation of customary first-class office artwork
and as otherwise approved by Landlord, such as customary as approved by
Landlord, Tenant shall not mark, drive nails, screw or drill into the
partitions, woodwork or plaster or in any way deface the Premises. Tenant shall
not cut or bore holes for wires. Tenant shall not affix any floor covering to
the floor of the Premises in any manner except as approved by Landlord. Tenant
shall repair any damage resulting from non-compliance with this rule.

     16.  Unless approved by Landlord, Tenant shall not install, maintain or
operate upon the Premises any vending machine; provided that Landlord pre-
approves Tenant's installation, maintenance and operation of snack, non-
alcoholic beverage, and coffee vending machines serving Tenant's employees.

     17.  Tenant shall store all its trash and garbage within its Premises.
Tenant shall not place in any trash box or receptacle any material which cannot
be disposed of in the ordinary and customary manner of trash and garbage
disposal.  All garbage and refuse disposal shall be made in accordance with
reasonable directions issued from time to time by Landlord.

     18.  Smoking is prohibited at all times in all areas of the Building,
including offices, restrooms, corridors, stairwells, lobbies and elevators. and
may be prohibited in all outside Common Areas of the Building Complex or
restricted by Landlord to specific locations designated by Landlord as smoking
areas. Tenant shall not cause or permit any noise (including playing of musical
instruments, radio or television) or objectionable odors to emanate from the
Premises which would annoy other tenants or create a public or private nuisance
and no cooking shall be done or permitted by any Tenant on the Premises, except
by the Tenant of Underwriters' Laboratory approved microwave oven or equipment
for brewing coffee, tea, hot chocolate and similar beverages shall be permitted
provided that such equipment and use is in accordance with all applicable
federal, state and city laws, codes, ordinances, rules and regulations.  Tenants
shall not conduct directly or indirectly any auction upon their premises, or
permit any other person to conduct an auction upon the premises.  Canvassing,
soliciting and peddling in the Building are prohibited and tenants shall
cooperate to prevent the same.

                                       2
<PAGE>

     19.  No animals, birds, or pets of any kind, excluding seeing eye dogs,
shall be allowed in a tenant's premises or the Building.

     20.  Tenant shall not use in any space or in the public halls of the
Building any hand trucks except those equipped with the rubber tires and side
guards or such other material-handling equipment as Landlord may reasonably
approve. Tenant shall not bring any other vehicles of any kind into the Building
and bicycles shall be used or stored only in areas designated by Landlord.

     21.  Tenant shall not use the name of the Building in connection with or in
promoting or advertising the business of Tenant except as Tenant's address.

     22.   The requirements of Tenant will be attended to only upon appropriate
application to the office of the Building by an authorized individual.  Except
as otherwise expressly set forth in the Lease, employees of Landlord shall not
perform any work or do anything outside of their regular duties unless under
special instruction from Landlord, and no employee of Landlord will admit any
person (Tenant or otherwise) to any office without specific instructions from
Landlord.  All contractors hired by Tenant to complete alterations to the
Premises shall adhere to the provisions of the Lease and these Rules and
Regulations, as well as such separate reasonable rules and regulations as
Landlord may adopt as requirements for contractors.

     23.  Tenant shall cooperate fully with the life safety plans of the
Building established and administered by Landlord. This includes participation
by Tenant and its employees in exit drills, fire inspections, life safety
orientations and other programs relating to fire safety that may be promulgated
by the Landlord.

     24.  Landlord may waive any one or more of these Rules and Regulations for
the benefit of any particular tenant or tenants, but no such waiver by Landlord
shall be construed as a waiver of such Rules and Regulations in favor of any
other tenant or tenants, nor prevent Landlord from thereafter enforcing any such
Rules and Regulations against any or all of the tenants of the Building.

     25.  These Rules and Regulations are in addition to, and shall not be
construed to in any way modify or amend, in whole or in part, the terms,
covenants, agreements and conditions of any lease of premises in the Building.

     26.  Landlord reserves the right to make such other and reasonable rules
and regulations as in its judgment may from time to time be needed for safety
and security, for care and cleanliness of the Building and for the preservation
of good order in and about the Building. Tenant agrees to abide by all such
rules and regulations in this Exhibit E stated and any additional rules and
regulations which are adopted.

     27.  Tenant shall be responsible for the observance of all of the foregoing
rules by Tenant's employees, agents, clients, customers, invitees and guests.

                                       3
<PAGE>

                              EXHIBIT F TO LEASE

                                     SNDA
                                     ----

                                       1
<PAGE>

                       SUBORDINATION, NONDISTURBANCE AND
                             ATTORNMENT AGREEMENT

     THIS AGREEMENT made this ___ day of _________________, 2000, between
GUARANTY FEDERAL BANK, F.S.B., a federal savings bank (hereinafter called
"Lender") and LIFEMINDERS.COM, INC., a Delaware corporation (hereinafter called
"Tenant") and DTC ASSOCIATES, LLC, a Virginia limited liability company
(hereinafter called "Landlord").

                         W I T N E S S E T H   T H A T:

     WHEREAS, Lender is the owner and holder of a Deed of Trust and Security
Agreement (hereinafter called the "Security Instrument"), dated September 10,
1999, in Book 11087, Page 0681, of the Real Property Records of Fairfax County,
Virginia, covering the real property described in Exhibit A and the buildings
                                                  ---------
and improvements thereon (hereinafter collectively called the "Mortgaged
Premises") securing the payment of a promissory note in the stated principal
amount of $17,985,000, payable to the order of Lender;

     WHEREAS, Tenant is the tenant under Lease Agreement (hereinafter called the
"Lease") dated _________________, 2000 by and between Landlord and Tenant,
covering certain property (hereinafter called the "Demised Premises") consisting
of a part of the Mortgaged Premises; and

     WHEREAS, Tenant, Landlord and Lender desire to confirm their understanding
with respect to the Lease and the Security Instrument;

     NOW, THEREFORE, in consideration of the mutual covenants and agreements
herein contained, Lender, Landlord and Tenant hereby agree and covenant as
follows:

     1.   Subordination.  The Lease now is, and shall at all times and for all
          -------------
purposes continue to be, subject and subordinate, in each and every respect, to
the Security Instrument, with the provisions of the Security Instrument
controlling in all respects over the provisions of the Lease, it being
understood and agreed that the foregoing subordination shall apply to any and
all increases, renewals, modifications, extensions, substitutions, replacements
and/or consolidations of the Security Instrument, provided that any and all such
increases, renewals, modifications, extensions, substitutions, replacements
and/or consolidations shall nevertheless be subject to the terms of this
Agreement.

     2.   Non-Disturbance.  So long as (i) Tenant is not in default (beyond any
          ---------------
period given Tenant to cure such default) in the payment of rent or additional
rent or in the performance of any of the other terms, covenants or conditions of
the Lease on Tenant's part to be performed, (ii) the Lease is in full force and
effect, and (iii) Tenant attorns to Lender or a purchaser of the Mortgaged
Premises as provided in Paragraph 3, then (a) Tenant's possession, occupancy,
use and quiet enjoyment of the Demised Premises under the Lease, or any
extensions or renewals thereof or acquisition of additional space which may be
effected in accordance with any option therefor in the Lease, shall not be
terminated, disturbed, diminished or interfered with by Lender in the exercise
of any of its rights under the Security Instrument, and (b) Lender will not join
Tenant as a party defendant in any action or proceeding for the purpose of
terminating Tenant's interest and estate under the Lease because of any default
under the Security Instrument.

     3.   Attornment.  If Lender shall become the owner of the Mortgaged
          ----------
Premises or the Mortgaged Premises shall be sold by reason of non-judicial or
judicial foreclosure or other proceedings brought to enforce the Security
Instrument or the Mortgaged Premises shall be conveyed by deed in lieu of
foreclosure, the Lease shall continue in full force and effect as a direct Lease
between Lender or other purchaser of the Mortgaged Premises, who shall succeed
to the rights and duties of Landlord, and Tenant.  In such event, Tenant shall
attorn to Lender or such purchaser, as the case may be, upon any such occurrence
and shall recognize Lender or such purchaser, as the case may be, as the
Landlord under the Lease.  Such attornment shall be effective and self-operative
without the execution of any further instrument on the part of any of the
parties hereto.  Tenant agrees, however, to execute and deliver at any time and
from time to time, upon the request of Landlord or of any holder(s) of any of
the indebtedness or other obligations secured by the Security Instrument or any
such purchaser, any instrument or certificate which, in the sole reasonable
judgment of the requesting party, is necessary or appropriate, in connection
with any such foreclosure or deed in lieu of foreclosure or otherwise, to
evidence such attornment, which instrument or certificate shall be in form and
content reasonably acceptable to Tenant.  Tenant hereby waives the provisions of
any statute or rule of law, now or hereafter in effect, which may give or
purport to give Tenant any right or election to terminate or otherwise adversely
affect the Lease and the obligations of Tenant thereunder as a result of any
such foreclosure or deed in lieu of foreclosure.

                                       2
<PAGE>

     4.   Obligations and Remedies.  If Lender shall become the owner of the
          ------------------------
Mortgaged Premises or the Mortgaged Premises shall be sold by reason of non-
judicial or judicial foreclosure or other proceedings brought to enforce the
Security Instrument or the Mortgaged Premises shall be conveyed by deed in lieu
of foreclosure, Lender or other purchaser of the Mortgaged Premises, as the case
may be, shall have the same remedies by entry, action or otherwise in the event
of any default by Tenant (beyond any period given Tenant to cure such default)
in the payment of rent or additional rent or in the performance of any of the
other terms, covenants and conditions of the Lease on Tenant's part to be
performed that Landlord had or would have had if Lender or such purchaser had
not succeeded to the interest of Landlord.  Upon attornment by Tenant as
provided herein, Lender or such purchaser shall be bound to Tenant under all the
terms, covenants and conditions of the Lease and Tenant shall have the same
remedies against Lender or such purchaser for the breach of an agreement
contained in the Lease that Tenant might have had under the Lease against
Landlord if Lender or such purchaser had not succeeded to the interest of
Landlord; provided, however, that Lender or such purchaser shall not be liable
or bound to Tenant:

          (a) for any act or omission of any prior landlord (including
Landlord); provided, however, nothing herein shall be deemed to be a waiver of
Tenant's rights or remedies in the event such act or omission is of a continuing
nature, such as, for example, Landlord's failure to fulfill a repair obligation,
and such default is not cured by Lender or such purchaser after Lender or such
purchaser acquires the Mortgaged Premises (however, Lender or such purchaser
shall in no event be liable for any tort claims which Tenant may have against
Landlord or any claims for liquidated damages which may be owing by Landlord
under the Lease); or

          (b) for any offsets or defenses which the Tenant might be entitled to
assert against Landlord; or

          (c) for or by any rent or additional rent which Tenant might have paid
for more than the current month to any prior landlord (including Landlord); or

          (d) by any amendment or modification of the Lease made without
Lender's consent, which consent shall not be unreasonably withheld or
conditioned; or

          (e) for any security deposit, rental deposit or similar deposit given
by Tenant to a prior landlord (including Landlord) unless such deposit is
actually paid over to Lender or such purchaser by the prior landlord; or

          (f) for the construction of any improvements required of Landlord
under the Lease in the event Lender or such purchaser acquires title to the
Mortgaged Premises prior to full completion and acceptance by Tenant of
improvements required under the Lease; provided, however, such lack of liability
on the part of Lender or such purchaser pursuant to this subparagraph shall not
affect Tenant's rights described in the Lease in the event of such failure to
complete such improvements as long as Tenant has provided all applicable notices
and cure periods as required under the Lease and this Agreement;  or

          (g) for any portion of the Allowance (as such term is defined in the
Lease) previously disbursed to Landlord by Lender pursuant to the Construction
Loan Agreement executed by and between Landlord and Lender; or

          (h) for the payment of any leasing commissions or other expenses for
which any prior landlord (including Landlord) incurred the obligation to pay; or

          (i) by any provision of the Lease restricting use of other properties
owned by Lender, as landlord.

     The person or entity to whom Tenant attorns shall be liable to Tenant under
the Lease only for matters arising during (but not after) such person's or
entity's period of ownership and such liability shall be limited as set forth
herein.

     5.   No Abridgment.  Nothing herein contained is intended, nor shall it be
          -------------
construed, to abridge or adversely affect any right or remedy of Landlord under
the Lease in the event of any default by Tenant (beyond any period given Tenant
to cure such default) in the payment of rent or additional rent or in the
performance of any of the other terms, covenants or conditions of the Lease on
Tenant's part to be performed.

     6.   Notices of Default to Lender.  Tenant agrees to give Lender a copy of
          ----------------------------
any default notice sent by Tenant under the Lease to Landlord.

     7.   Representations by Tenant.  Tenant represents and warrants to Lender
          -------------------------
that Tenant has validly executed the Lease; the Lease is valid, binding and
enforceable and is in full force and effect in accordance with its terms; the
Lease has not been amended except as stated herein; no rent under the Lease has
been paid more than thirty (30) days in advance of its due date; to the best of
Tenant's knowledge without any independent investigation there are no defaults
existing under the Lease; and Tenant, as of this date, has no charge, lien,
counterclaim or claim of offset under the Lease, or otherwise, against the rents
or other charges due or to become due under the Lease.

                                       3
<PAGE>

     8.   Rent Payment.  If Lender shall become the owner of the Mortgaged
          ------------
Premises or the Mortgaged Premises shall be sold by reason of non-judicial or
judicial foreclosure or other proceedings brought to enforce the Security
Instrument or the Mortgaged Premises shall be conveyed by deed in lieu of
foreclosure, Tenant agrees to pay all rents directly to Lender or other
purchaser of the Mortgaged Premises, as the case may be, in accordance with the
Lease immediately upon notice of Lender or such purchaser, as the case may be,
succeeding to Landlord's interest under the Lease.  Tenant further agrees to pay
all rents directly to Lender immediately upon notice that Lender is exercising
its rights to such rents under the Security Instrument or any other loan
documents (including but not limited to any Assignment of Leases and Rents)
following a default by Landlord or other applicable party.  Tenant shall be
under no obligation to ascertain whether a default by Landlord has occurred
under the Security Instrument or any other loan documents.  Landlord waives any
right, claim or demand it may now or hereafter have against Tenant by reason of
such direct payment to Lender and agrees that such direct payment to Lender
shall discharge all obligations of Tenant to make such payment to Landlord.

     9.   Notice of Security Instrument.  To the extent that the Lease shall
          -----------------------------
entitle Tenant to notice of any deed of trust or security agreement, this
Agreement shall constitute such notice to the Tenant with respect to the
Security Instrument and to any and all other deeds of trust and security
agreements which may hereafter be subject to the terms of this Agreement.

     10.  Landlord Defaults.  Tenant agrees with Lender that effective as of the
          -----------------
date of this Agreement: (i) Tenant shall not take any steps to terminate the
Lease for any default by Landlord or any succeeding owner of the Mortgaged
Premises until after giving Lender written notice of such default, stating the
nature of the default and giving Lender thirty (30) days from receipt of such
notice to effect cure of the same, or if cure cannot be effected within said
thirty (30) days due to the nature of the default, Lender shall have a
reasonable time to cure (not to exceed a total of 120 days) provided that it
commences cure within said thirty (30) day period of time and diligently carries
such cure to completion; and (ii) notice to Landlord under the Lease (oral or
written) shall not constitute notice to Lender.

     11.  Liability of Lender. If Lender shall become the owner of the Mortgaged
          -------------------
Premises or the Mortgaged Premises shall be sold by reason of foreclosure or
other proceedings brought to enforce the Security Instrument or the Mortgaged
Premises shall be conveyed by deed in lieu of foreclosure, Tenant agrees that,
notwithstanding anything to the contrary contained in the Lease, after such
foreclosure sale or conveyance by deed in lieu of foreclosure, Lender shall have
no personal liability to Tenant under the Lease and Tenant shall look solely to
the estate and property of Landlord in the Mortgaged Premises, to the net
proceeds of sale thereof or the rentals received therefrom, for the satisfaction
of Tenant's remedies for the collection of a judgment or other judicial process
requiring the payment of money by Landlord in the event of any default or breach
by Landlord with respect to any of the terms, covenants, and conditions of the
Lease to be observed or performed by Landlord and any other obligation of
Landlord created by or under the Lease, and no other property or assets of
Lender shall be subject to levy, execution or other enforcement procedures for
the satisfaction of Tenant's remedies.  Further, in the event of any transfer by
Lender of Landlord's interest in the Lease, Lender (and in the case of any
subsequent transfers or conveyances, the then assignor), including each of its
partners, officers, beneficiaries, co-tenants, shareholders or principals (as
the case may be) shall be automatically freed and released, from and after the
date of such transfer or conveyance, of all liability for the performance of any
covenants and agreements which accrue subsequent to the date of such transfer of
Landlord's interest.

     12.  Notice.  Any notice or communication required or permitted hereunder
          ------
shall be given in writing, sent by (a) personal delivery, or (b) expedited
delivery service with proof of delivery, or (c) United States mail, postage
prepaid, registered or certified mail, addressed as follows:

     To Lender:          Guaranty Federal Bank, F.S.B.
                         8333 Douglas Avenue
                         Dallas, Texas 75225
                         Attention: Commercial Real Estate

     To Tenant:          Lease Precommencement Address:
                         ------------------------------
                         Lifeminders.com, Inc.
                         1110 Herndon Parkway, Suite 300
                         Herndon, Virginia 20170
                         Attention: Mr. David N. Mahoney, COO

                         Lease Post Commencement Address:
                         --------------------------------
                         Lifeminders.com, Inc.
                         13530 Dulles Technology Drive, Suite 500
                         Herndon, Virginia

                                       4
<PAGE>

     With copy to:       Shaw Pittman
                         1676 International Drive
                         McLean, Virginia 22102-4835
                         Attention: Craig Chason, Esquire

or to such other address or to the attention of such other person as hereafter
shall be designated in writing by the applicable party sent in accordance
herewith.  Any such notice or communication shall be deemed to have been given
and received either at the time of personal delivery or, in the case of delivery
service or mail, as of the date of first attempted delivery at the address and
in the manner provided herein.

     13.  No Amendment, Assignment or Subletting of Lease.  Lender and Tenant
          -----------------------------------------------
agree that Tenant's interest in and obligations under the Lease shall not be
altered or modified without the prior written consent of Lender.  Lender and
Tenant also agree that Tenant shall neither assign the Lease or allow it to be
assigned in any manner nor sublet the Demised Premises or any part thereof
except in accordance with the terms of the Lease.

     14.  No Amendment or Termination of Lease.  Lender and Tenant agree that
          ------------------------------------
Tenant's interest in and obligations under the Lease shall not be altered or
modified without the prior written consent of Lender, nor shall Landlord and
Tenant enter into a consensual termination of the Lease without the prior
written consent of Lender.

     15.  Modification.  This Agreement may not be modified orally or in any
          ------------
manner other than by an agreement in writing signed by the parties hereto or
their respective successors in interest.

     16.  Successor Lender.  The term "Lender" as used throughout this Agreement
          ----------------
includes any successor or assign of Lender and any holder(s) of any interest in
the indebtedness secured by the Security Instrument.

     17.  Successors and Assigns.  This Agreement shall inure to the benefit of
          ----------------------
and be binding upon the parties hereto, their successors and assigns, and any
purchaser or purchasers at foreclosure of the Mortgaged Premises, and their
respective successors and assigns.

     18.  Paragraph Headings.  The paragraph headings contained in this
          ------------------
Agreement are for convenience only and shall in no way enlarge or limit the
scope or meaning of the various and several paragraphs hereof.

     19.  Gender and Number.  Within this Agreement, words of any gender shall
          -----------------
be held and construed to include any other gender, and words in the singular
number shall be held and construed to include the plural and words in the plural
number shall be held and construed to include the singular, unless the context
otherwise requires.

     20.  Applicable Law.  This Agreement and the rights and duties of the
          --------------
parties hereunder shall be governed by all purposes by the law of the state
where the Mortgaged Premises is located and the law of the United States
applicable to transactions within such state.

     21.  Counterparts.  This Agreement may be executed in multiple counterparts
          ------------
and by the different parties hereto in separate counterparts, each of which
shall for all purposes be deemed to be an original and all of which together
shall constitute but one and the same instrument, with the same effect as if all
parties to this Agreement had signed the same signature page.

     IN WITNESS WHEREOF, the parties hereto have hereunto caused this Agreement
to be duly executed as of the day and year first above written.

                         LENDER:

                         GUARANTY FEDERAL BANK, F.S.B., a federal savings bank

                         By: _____________________________________
                            Name: _______________________________
                            Title: ________________________________

                         TENANT:

                         LIFEMINDERS.COM, INC., a Delaware corporation

                                       5
<PAGE>

                         By: _____________________________________
                            Name: _______________________________
                            Title: ________________________________

                         DTC ASSOCIATES, LLC, a Virginia limited liability
                         company

                         By:  MGA Development Associates, L.P., a Colorado
                              limited partnership, Manager

                              By: ____________________________________
                                    Donald E. Spiegleman
                                    Authorized Signatory

THE STATE OF TEXAS       )
                         )
COUNTY OF DALLAS         )

     This instrument was acknowledged before me on _________________, 2000, by
__________________, _________________ of GUARANTY FEDERAL BANK, F.S.B., a
federal savings bank, on behalf of said federal savings bank.

                              _______________________________________
                              Notary Public, State of Texas

                              _______________________________________
                                    (printed name)

My Commission Expires:

____________________

COMMONWEALTH OF VIRGINIA)
                              )
COUNTY OF _____________       )

     This instrument was acknowledged before me on _____________, 2000, by
__________________, __________________ of Lifeminders.com, Inc., a Delaware
corporation, on behalf of said corporation.

                              _____________________________________
                              Notary Public, State of __________________

                              _____________________________________
                                    (printed name)

My Commission Expires:

____________________

THE STATE OF COLORADO    )
                         )
COUNTY OF DENVER         )

                                       6
<PAGE>

     This instrument was acknowledged before me this _____ day of ____________,
2000 by Donald E. Spiegleman, Authorized Signatory of MGA Development
Associates, L.P., a Colorado limited partnership, on behalf of said limited
partnership,  in its capacity as manager of DTC Associates, LLC, a Virginia
limited liability company.

                              ____________________________________
                              Notary Public, State of _____________

My Commission Expires:        ____________________________________
                                    (printed name)
_____________________

                                       7
<PAGE>

                              EXHIBIT G TO LEASE

                           FORM OF LETTER OF CREDIT
                           ---- -- ------ -- ------

                             _______________, 2000

DTC ASSOCIATES, LLC
c/o Miller Global Properties, LLC
4643 S. Ulster Street, Suite 1500, Denver, CO 80237

RE:  Letter of Credit No. ___________

Gentlemen:

     We hereby issue in your favor, at the request and for the account of
LIFEMINDERS.COM, INC., a Delaware corporation  our irrevocable Letter of Credit
in the amount of $                                    which is available against
presentation of your sight draft. The draft must be accompanied by:

1.   This Letter of Credit No. _____________; and

2.   A notarized certification signed as "Authorized Signatory " on behalf of
DTC Associates, LLC, or an officer (or partner, if such entity is a partnership
or member if a limited liability company) of its transferee or assignee, stating
essentially as follows:

     "The undersigned is the owner of the property described in the Office Lease
dated _________________ by and between [Landlord], as Landlord, and
LIFEMINDERS.COM, INC., a Delaware corporation as Tenant (the "Lease ").  The
amount requested by the draft accompanying this statement is the amount to which
the undersigned is entitled under the terms of the Lease as a result of an Event
of Default under the Lease and the undersigned requests payment of the enclosed
draft under the enclosed Letter of Credit."

     This Letter of Credit shall be subject to the Special Conditions set forth
on Exhibit 1, such exhibit being considered a part hereof and incorporated
herein by reference.

     We hereby agree that all drafts drawn under and in compliance with the
terms of this credit shall meet with honor upon presentation and delivery of
documents on or before 5:00 p.m., Denver time, _____[DATE]_______________, as
specified to the drawee.

                              [BANK]

                              By:
                              Title:

                                       8
<PAGE>

                                   EXHIBIT 1

                    To Letter of Credit No. ______________

     The Letter of Credit shall be governed by the following Special Conditions:

     1.   This Letter of Credit shall be governed by and construed in accordance
with the laws of the State of Colorado, including specifically, but not limited
to, C.R.S. (S)4-5-101, et seq., entitled Uniform Commercial Code -- Letters of
Credit, as amended.  The provisions of Uniform Customs and Practice for
Documentary Credits, I.C.C., shall not be applicable to this Letter of Credit.

     2.   Issuer agrees that it may not defer honor beyond the close of the
first banking day after presentment of a sight draft drawn hereunder and
accompanying documents.

     3.   This Letter of Credit shall be transferable and assignable to any
person or entity who is the successor or assignee of the interest of landlord
under the Lease entered into on or about ___________, between DTC Associates,
LLC and LIFEMINDERS.COM, INC, a Delaware corporation.  Such transfer shall be
accomplished by providing ___________[BANK]_____________ with the appropriate
transfer form and the original letter of credit for endorsement; provided,
however, that such transfer shall not be subject to the approval of
______________[BANK]________________.

                                       2
<PAGE>

                              EXHIBIT H TO LEASE

                               BUILDING SIGNAGE
                               ----------------

Tenant name identification signage shall be electrified and internally
illuminated, surface mounted to the top (roof) spandrel panel, at a location
mutually agreed upon.  The sign shall be at the maximum size approved by Fairfax
County and the Dulles Technological Associates Architectural Control Committee.
The sign shall be fabricated and installed by a commercial sign contractor.  The
sign shall be subject to Landlord's reasonable approval as to design, color,
method of illumination and method of attachment.

                                       1
<PAGE>

                              EXHIBIT I TO LEASE

                           JANITORIAL SPECIFICATIONS
                           -------------------------

A.   DAILY -   Monday through Friday, except legal holidays.

     1.   Empty waste baskets, clean ashtrays.

     2.   Dust accessible areas of desk tops.

     3.   Vacuum carpet in elevator lobbies, reception areas and other high-
          traffic areas.

B.   WEEKLY

     1.   Dust accessible areas of furniture, convectors and other furnishings.

     2.   Vacuum office area carpeting.

C.   MONTHLY

     1.   Mop and buff tile floors.

     2.   Dust Venetian blinds, window frames and exterior of lighting fixtures.

     3.   Spot clean walls.

     4.   Clean telephones.

D.   QUARTERLY

     1.   Clean and refinish tile floors where necessary.

     2.   Clean baseboards.

     3.   Wash interior of windows

E.   SEMI-ANNUALLY

     1.   Wash exterior of windows.

F.   ANNUALLY

     1.   Wash light fixtures and lenses.

     2.   Clean Venetian blinds.

NOTE:  Cleaners will not remove papers or other materials from surfaces to be
cleaned, dusted or vacuumed.  Trash not in wastebaskets should be clearly marked
"TRASH."  Cleaning of private kitchens and baths is the responsibility of the
Tenant.

                                       1
<PAGE>

                              EXHIBIT J TO LEASE

                                  WORK LETTER
                                  -----------

                               November 9, 2000

Lifeminders.com, Inc.
1110 Herndon Parkway
Suite 300
Herndon, Virginia 20170
Attention: Mr. David N. Mahoney, COO

Re:       Tenant:  Lifeminders.com, Inc., a Delaware corporation

          Premises: approximately 131,841 rentable square feet consisting of
                    floors 6,5,4 and 3, of which a portion of the Premises
                    consisting of 65,799 rentable square feet of space
                    consisting of floors 6 and 5 shall be referred herein and
                    depicted on Exhibit A as "Phase I " and the remaining 66,042
                    rentable square feet of space (floors 4 and 3) shall be
                    referred herein and depicted on Exhibit A as "Phase II "
                    (Phase I and Phase II collectively referred to as the
                    "Premises ")

          Building: Dulles Executive Plaza I, 13530 Dulles Technology Drive,
                    Herndon, Virginia

Gentlemen:

          Concurrently herewith, you ("Tenant ") and the undersigned ("Landlord
") have executed a Lease (the "Lease ") covering the Premises (the provisions of
the Lease are hereby incorporated by reference as if fully set forth herein and
initially capitalized words not defined have the same meaning set forth in the
Lease).  In consideration of the execution of the Lease, Landlord and Tenant
mutually agree as follows:

1.  Space Planning and Engineering
    ------------------------------

          1.1    Landlord has provided to Tenant the architectural and
engineering drawings for the base building improvements for the Building Complex
to be completed by Landlord ("Landlord's Drawings ")(as further described on
Exhibit 4 to this Work Letter), as prepared by Davis Carter Scott (such
architectural firm or its replacement, if replaced by Landlord prior to
completion of construction, is referred to as the "Landlord's Architect "). The
work to be completed by Landlord in accordance with Landlord's Drawings is
referred to as the "Building Improvements." If Tenant desires that the
Landlord's Drawings be modified in any manner, then Landlord shall reasonably
endeavor to address Tenant's concerns. If Landlord's sole reason for rejecting a
proposed change is the increased cost that will be incurred if the change is
adopted, and if Tenant agrees to pay the entire incremental cost attributable to
such change, then Landlord shall agree to adopt the proposed change and Tenant
shall thus pay such entire incremental cost within 30 days after Landlord's
submission of a statement of the additional expenses attributable to such
changes, as additional rent. Landlord shall have the right to make changes and
modifications in the base building improvements during construction and Landlord
shall provide copies to Tenant of modifications to Landlord's Drawings promptly
as and when available to reflect such modifications for portions of the drawings
applicable to the Premises as soon as possible and, if possible, prior to
commencing such work; provided that Tenant shall have the right to approve
(which approval shall not be unreasonably withheld, conditioned or delayed)
substantial changes to the Building Complex which materially adversely affect
Tenant's use of the Premises or the cost or scope of the Tenant Work, other than
changes required by Applicable Laws or as required during construction to adjust
to field conditions. Landlord shall complete the Building Improvements in a good
and workmanlike manner in accordance with Applicable Laws, in a manner
consistent with construction practices for a "Class A" building in the Northern
Virginia area and in accordance with the Declaration.

          1.2    Tenant shall retain Studios Architecture or, at its option,
another architect reasonably approved by Landlord as Tenant's architect
("Tenant's Architect ").  Tenant shall retain WFT Engineering or, at its option,
another engineer reasonably approved by Landlord as Tenant's engineer ("Tenant's
Engineer") to perform mechanical, electrical, plumbing, and  life safety; in
addition, Tenant shall retain Landlord's designated structural engineers to
provide engineering design review pertaining to structural design issues (the
"Structural Engineers").  Tenant shall provide to Landlord the Tenant-approved
space plans for the Premises (collectively referred to herein as "Space Plans ")
prepared by Tenant's Architect by the Space Plan Deadline set forth on Exhibit
6.  The Space Plans shall contain

                                       1
<PAGE>

information specified in Exhibit 1 and shall be sufficiently complete to permit
Landlord to review such drawings for the purpose of determining conformity with
the base building specifications for the Building and for the purposes described
in Section 1.3 below. The Space Plans shall be prepared by Tenant's Architect at
Tenant's sole cost and expense, subject to Landlord's payment of the Allowance
as hereinafter provided; Landlord may deduct from the Allowance Landlord's
actual costs paid to third parties for assistance in review of the Space Plans
if reasonably required by Landlord.

          1.3    Within 5 business days after receipt by Landlord of the Space
Plans, Landlord shall review the Space Plans and confer with Tenant concerning
such review. Landlord shall respond to such submission, in accordance with the
scope of review set forth in this Section 1.3, within 5 business days after
Landlord's receipt thereof (including Landlord's receipt of Tenant's written
response to each of Landlord's prior comments).  Such review and resubmission
process shall continue until the Space Plans (including Tenant's responses to
Landlord's comments on such Space Plans) are approved by Landlord.  Landlord's
approval shall not be unreasonably withheld, conditioned or delayed and the
scope of Landlord's review of Tenant's proposed Space Plans shall be limited to
only those portions thereof that (i) are readily visible to the exterior of the
Building or the common and public areas thereof, or (ii) are structural in
nature, or (iii) affect the electrical, mechanical, fire or life safety systems
within the Building, (iv) are related to conformance with all applicable
building, zoning and other codes or regulations affecting the Building, (v) do
not contain all of the information specified in Exhibit 1 or are not
sufficiently complete to permit Landlord to review them for the purposes set
forth therein; (vi) indicate space usages inconsistent with the Permitted Use or
Ancillary Uses, (vii) are necessary to determine consistency with class A office
space finishes and the requirements of Exhibit 7 (the "Landlord's Scope of
Review ").   The Structural Engineers shall advise Landlord and Tenant whether
the base building structure and systems will have to be supplemented or modified
in order to allow installation of work shown on the Space Plans.  If Landlord
objects to the draft Space Plans or requires changes, within Landlord's Scope of
Review, Tenant shall revise the Space Plans accordingly within 5 business days
of receipt of being informed of such determination and resubmit them to Landlord
and the review procedure and time frames set forth above shall be repeated.  Any
delay by Landlord in responding within the applicable periods or delays arising
from errors by Landlord in such review process shall be deemed Landlord Delay
to the extent that such delay is beyond the specified periods and results in
delaying approval of the Approved Space Plans beyond the Space Plan Deadline set
forth in Exhibit 6.  Tenant shall pay all reasonable costs and expenses incurred
by Landlord in connection with review and approval of the Space Plans by the
Engineers, which amounts shall be paid from the Allowance,  provided, however,
that Tenant's liability for Landlord's costs and expenses relating to the review
of any or all of Tenant's plans and drawings, including the Space Plans, shall
not exceed $25,000 (based on an itemized statement of such costs with
engineering fees billed at $______ per hour).  When approved by Landlord and
Tenant, the Space Plans shall be acknowledged as such by Landlord and Tenant
signing each sheet therefor and such approved drawings shall be deemed the
"Approved Space Plans."

          1.4    On or before the Phase 1 Draft Architectural Drawings Deadline
set forth in Exhibit 6, Tenant shall provide Landlord with architectural working
drawings and engineering working drawings for Phase 1.   On or before the Phase
II Draft Architectural Drawings Deadline set forth in Exhibit 6, Tenant shall
provide Landlord with architectural working drawings and engineering working
drawings for Phase II.  The architectural working drawings (collectively, the
"Architectural Working Drawings") shall be prepared by Tenant's Architect and
the structural, plumbing, fire protection, mechanical controls, electrical and
life safety engineering drawings (collectively, the "Engineering Working
Drawings") shall be prepared by Tenant's Engineer, all of which shall be
prepared substantially in the form provided in Exhibit 1.  The Architectural
Working Drawings shall be coordinated by Tenant's Architect with Landlord's
Drawings and the Approved Space Plans.  The Architectural Working Drawings and
the Engineering Working Drawings shall be logical extensions of the Approved
Space Plans for the Premises approved by Tenant for review by Landlord
substantially in the form provided in Exhibit 1.  Tenant's Architect shall be
responsible for any conflicts between the Architectural Working Drawings and
field conditions (unless such field conditions materially vary from Landlord's
Drawings, as modified).  Tenant shall be responsible for the consistency between
the Architectural Working Drawings and the Engineering Working Drawings,
conflicts with Building Improvements and field conditions and for the
Architectural Working Drawings and the Engineering Working Drawings complying
with building code provisions.  Subject to Section 1.1, Landlord shall notify
Tenant's Architect of changes in Landlord's Drawings affecting the Tenant Work
within five (5) business days of an actual change in such drawings (not just a
proposed change), so as to minimize interference with or delay to completion of
Tenant's Working Drawings.  Any problems caused by any inconsistency of the
drawings shall be Tenant's sole responsibility (subject to Tenant or Tenant's
Architect receiving Landlord's Drawings and changes in Landlord's Drawings).  If
the review by Landlord or Landlord's engineers, if applicable, uncovers design
errors, Landlord shall give notice thereof, including any review comments,
within 10 business days after Landlord's receipt of Architectural Working
Drawings and the Engineering Working Drawings submitted by Tenant.  If Landlord
does not reply within such period, it shall be presumed that Landlord has no
objection thereto, however, such approval shall not limit Landlord's right to
request changes in the future in the event design errors are discovered (which
request shall be made as soon as practicable following such discovery) and
Tenant shall not be obligated to make changes as to which notice is given beyond
such 10 day period unless the safety of the Tenant Work is affected or that are
required by Applicable Laws.  If Landlord notifies Tenant

                                       2
<PAGE>

of design errors pursuant to this Section (within the time period, as
applicable), Tenant shall revise the Architectural Working Drawings and the
Engineering Working Drawings accordingly, and resubmit them to Landlord only for
review of those design issues noted by Landlord after Landlord's initial review
of the Working Drawings. Landlord shall provide written approval or comments
within 3 business days of Tenant's resubmission and the review procedure set
forth above shall be repeated. Delay caused by such revisions shall be deemed
Tenant Delay. When approved (or deemed approved) by Landlord and Tenant, such
drawings shall be deemed the "Final Working Drawings ." Tenant shall
simultaneously submit its Working Drawings to Landlord for review, to Tenant's
contractor for final pricing, and for building permit review. Landlord
acknowledges that in order to maintain its schedule, Tenant may submit its
Working Drawings for pricing and permitting simultaneously with submittal to
Landlord. However, any revisions required by Landlord as a result of its
approval shall be incorporated by Tenant into pricing and permitting submittals
and any delays shall be deemed Tenant Delay.

          1.5    Changes to the Final Working Drawings, except for minor changes
not affecting the Building mechanical, electrical or life safety systems or the
structure of the Building, may be made only upon prior written approval of
Landlord, which shall not be unreasonably withheld, conditioned, or delayed.
Landlord acknowledges that time is of the essence, and shall respond  (in
writing or by oral communication thereafter confirmed in writing) to all written
requests for changes within 5 business days of Landlord's receipt of the same.
If Landlord does not respond within such period, Landlord shall be deemed to
have consented to the requested changes.  Any delay in completion of the Tenant
Work or the Building Improvements which results from any such changes or the
process of approval or disapproval (other than caused by Landlord Delay or Force
Majeure) shall be deemed Tenant Delay.  Landlord's review of the Space Plans,
Architectural Working Drawings, Engineering Working Drawings or Final Working
Drawings shall not imply approval by Landlord for their completeness, design
sufficiency, or as to compliance with the requirements of applicable codes,
rules, or regulations of any governmental agencies having jurisdiction thereof
now in effect or which may hereafter be in effect.

2.  Tenant Work and Finish Allowance
    --------------------------------

          2.1    Tenant shall enter into contracts for construction services to
complete the Tenant Work with contractors and subcontractors selected by Tenant
based on competitively bidding the work, provided that (i) in bidding to a
proposed general contractor and subcontractors, Tenant shall include Landlord's
general contractor, Centex Construction Company, and mechanical, electrical,
plumbing, sprinkler, fire and life safety alarm subcontractors in the bidding
process, (ii) Tenant shall use Landlord's mechanical, electrical, and plumbing
subcontractors if their bids are substantially equal to that of other bidders,
(iii) Tenant shall use Landlord's HVAC control systems subcontractor and
sprinkler subcontractor if their bids are not more than 10% higher than the
lowest other respective bids, and (iv) Tenant shall use the subcontractors and
materials vendors used by Landlord for fire and life safety alarm if their bids
are not more than 10% higher than the lowest other respective bids, and, if more
than 10% higher, Landlord's subcontractors and materials vendors shall be used
by Tenant solely for any tie-in to the fire and life safety alarm system.
Tenant shall provide Landlord with copies of all bids received by Tenant prior
to award for Landlord's review.  The contractor and subcontractors selected by
Tenant in accordance with the foregoing are referred to collectively as
"Tenant's Contractors "; provided, Tenant acknowledges and agrees that, to the
extent Tenant's Contractors are other than those used by Landlord, any delays in
Landlord having inspections completed or obtaining a final certificate of
occupancy for the Building caused by or arising out of the use of Tenant's
Contractors shall be deemed Tenant Delay.  Landlord and Tenant shall cooperate
with each other in coordinating any required inspections to minimize delay for
either party.  Tenant's Contractors will be required to adhere to the
requirements set forth on Exhibit 2 and shall perform all work in a manner
consistent with practices in other first class buildings in the suburban
northern Virginia area) (collectively, "Requirements ").  The contract with the
general contractor (the "Contract ") will incorporate (directly or indirectly by
reference) the provisions of the Requirements and all subcontracts shall be
subject to the provisions of the Contract and the Requirements.  Prior to
execution of the Contract, Tenant will provide a copy to Landlord.  Landlord
will review the Contract for compliance with the Requirements and advise Tenant
of Landlord's approval or required changes within 10 business days of receipt;
if Landlord fails to respond within such period, Landlord shall be deemed to
approved such Contract.

          2.2    Tenant's Contractors will be obligated to cooperate with
contractors employed by Landlord who are completing work in the Building
("Landlord's Contractors ") and such Contractors will each conduct their
respective work in an orderly fashion and manner so as not to unreasonably
interfere with the other.

          2.3    Tenant assumes full responsibility for Tenant's Contractor's
performance of all work,  including compliance with Applicable Laws, and for all
Tenant's Contractors' property, equipment, materials, tools or machinery placed
or stored in the Premises during the completion thereof (subject to the
provisions regarding Builder's Risk insurance), subject to the insurance and
waiver of subrogation provisions of the Lease.  All such work is to be performed
in a good and workmanlike manner consistent with first class standards.

                                       3
<PAGE>

          2.4    Landlord shall provide Tenant's Contractor with access to Phase
I on or before the Phase I Early Delivery Date set forth on Exhibit 6 for the
limited purpose of partition layout work and other pre-construction activities,
but no other work shall be permitted without Landlord's express written
approval. By such date, Landlord shall have installed and sealed the permanent
roof systems and installed and sealed all windows in Phase I and completed other
work to the extent necessary to permit Tenant's Contractors to commence such
partition layout work with respect to Phase I. Landlord shall, as of the Phase I
Early Delivery Date, provide clear access to Phase I, to include, at no cost or
expense to Tenant, non-exclusive use of an elevator, to the extent available,
and all utilities necessary and required to complete such pre-construction work
and the rest of the Tenant Work as of the Phase I Delivery Date as set forth on
Exhibit 6.

         2.5    The date on which a portion of the Premises is made available by
Landlord to Tenant for completion of the Tenant Work (other than the partition
layout work referred to above) subject only to work that can be completed by
Landlord's Contractor while Tenant's Contractors are completing Tenant Work in
the Premises, is referred to as the "Delivery Date " for such portion of the
Premises. The Phase I Delivery Date be on or before the Phase I Delivery Date as
set forth on Exhibit 6. The Phase II Delivery Date be on or before the Phase II
Delivery Date set forth on Exhibit 6. Landlord shall provide Tenant with notice
at least 60 days prior to the estimated Delivery Date of each Phase of the
Building Improvements on the Premises. Landlord shall provide Tenant with
written to Tenant when Landlord has determined that Landlord has completed such
of the Building Improvements that the Phase 1 Delivery Date or the Phase II
Delivery Date have been achieved. Following receipt of such notice and prior to
Tenant's Contractors commencing the Tenant Work, the representatives of Landlord
and Tenant shall jointly inspect the Premises with Landlord's Architect and, at
Tenant's option, Tenant's Architect, to and develop a list of items of Building
Improvements for the Building Complex which must be completed prior to Tenant
having Tenant's Contractors commence work on the respective floor and those
items that can be completed by Landlord's Contractor while Tenant's Contractors
are completing Tenant Work in the Premises. Upon Landlord completing all items
which must be completed prior to Tenant having Tenant's Contractors commence
work on the respective floor, the respective Delivery Date shall be deemed to
have occurred. In the event of a dispute, Landlord's Architect and Tenant's
Architect shall mutually resolve such dispute and if the Architects cannot agree
upon a resolution, the Architects shall jointly appoint an independent architect
whose determination shall be binding on the parties. Landlord and Tenant shall
share equally the cost of any required neutral independent architect.

          2.6    Following each Delivery Date, Landlord shall complete the
remaining Building Improvements with reasonable diligence as well as latent
defects discovered after the Delivery Date.  Following the Delivery Date, Tenant
is responsible for repair of damage caused by Tenant's Contractors in the
Building or Premises. Following the Delivery Date, Tenant is responsible for the
diligent completion of all tenant work substantially in accordance with the
Final Working Drawings (the "Tenant Work "), at its sole cost and expense,
subject to Landlord's payment of the Allowance.   Tenant's use and occupancy of
the portion of the Premises following the Delivery Date for such portion is
subject to all of the terms and provisions of the Lease (except for Tenant's
obligation to pay Base Rent and utilities, which shall be governed by the
provisions of Section 3 below). Tenant will cause Tenant's Contractors to: (i)
conduct work so as not to unreasonably interfere with any other construction
occurring in the Building (including remaining Building Improvements in the
Premises); (ii) comply with the Requirements; (iii) reach reasonable agreement
with Landlord's Contractors as to the terms and conditions for hoisting, systems
interfacing, and use of temporary utilities; and (iv) deliver to Landlord such
evidence of compliance with the provisions of this paragraph as Landlord may
reasonably request.

          2.7    Any delay by Landlord in meeting the deadlines set forth in
Sections 2.4 and 2.5 above, as listed on Exhibit 6, shall be deemed Landlord
Delay, with the consequences provided herein for Landlord Delay (but such delay
shall not be deemed a default by Landlord or make Landlord liable for damages
arising from such delay).

3.  Commencement Date.
    ------------------

          3.1    The Commencement Date (as the same may be extended as provided
below) shall be the date that is the earlier to occur of (a) the date on which
Tenant occupies all or substantially all of Phase I for the normal conduct of
Tenant's business, and (b) the later of (i) September 18, 2000 or (ii) the date
on which Landlord has substantially completed the Building Improvements for
Phase 1; provided, the later of (i) and (ii) shall be extended on a day-for-day
basis for each day of actual delay in the performance of the Tenant Work
resulting from Net Landlord Delay (as defined in Section 4.6 below).

         3.2    The Phase II Completion Date shall be the date that is the
earlier to occur of (a) the date on which Tenant occupies all or substantially
all of Phase II for the normal conduct of Tenant's business, and (b) the later
of (i) January 1, 2001 and (ii) the date on which Landlord has substantially
completed the Building Improvements for Phase II; provided, the later of (i) and
(ii) shall be extended on a day-for-day basis for each day of actual delay in
the performance of the Tenant Work resulting from Net Landlord Delay.

                                       4
<PAGE>

         3.3    The Building Improvements shall be deemed to be substantially
complete for Phase I when (i) Phase I and the parking garage are accessible by
Tenant and the non-completion of any Building Improvements to be done does not
materially and adversely affect Tenant's use, occupancy and enjoyment of Phase I
and the parking garage for the normal conduct of Tenant's business operations;
(ii) the portions of the parking garage assigned to Tenant are substantially
free from debris; (iii) the Building's ground floor lobby, public areas on the
ground floor (including the Building's main entrance) and the public areas on
Phase I floors to be occupied by Tenant are substantially completed (to the
extent to be completed by Landlord), with all finish items substantially
completed, and such floors shall be substantially free of construction debris
and available for use by the public, and all loading docks and those portions of
the garage to be used by Tenant shall have been substantially completed and be
accessible and usable for loading and parking purposes; (iv) core and shell, and
the Building standard mechanical, electrical, HVAC, fire and life safety, and
plumbing systems, pipes, and conduits that are provided by Landlord in the
operation of the Building (the "Base Building Systems") are substantially
completed and operating, subject, however, to such balancing as may be necessary
for the HVAC systems and subject to completion of work by Tenant that is
required for full operation of such systems; (v) all facilities and systems
servicing the Building that pass through Phase I or any part thereof (exclusive
of Common Areas, such as chases and Building equipment rooms that are not
considered part of the Premises) shall have been enclosed and no access through
Phase I that will materially interfere with Tenant's use thereof for the
purposes intended is required to complete the same, and the work remaining to be
done in the Building shall be of such nature as will not materially and
adversely interfere in a substantial and continuing manner with Tenant's use and
occupancy of Phase I for the normal conduct of Tenant's business; (vi) all
stairways and rooms located in the Building core on all Phase 1 floors to be
occupied in whole or in part by Tenant, including mechanical rooms, toilet
rooms, electrical closets, janitorial closets, freight elevator anterooms and
elevator cars shall have been substantially completed with the building standard
finishes, fixtures and accessories corresponding to each particular core area
(to the extent such work is to be completed by Landlord); and (vii) all
approvals, certificates of occupancy and permits (other than Tenant's business
licenses and certificates of occupancy pertaining to the completion of Tenant
Work), and those permits and approvals from the appropriate governmental
authorities pertaining to the Building Improvements or other improvements to be
constructed by Landlord required for the legal and practical occupancy of Phase
1 (except for such permits which by their terms cannot be issued until Tenant
Work is completed) . The Building Improvements shall be deemed to be
substantially complete with respect to Phase II when conditions (i)- (vii) above
are satisfied, except that all references to "Phase I" shall deleted and
replaced with "the Premises".

         3.4    Landlord presently anticipates that the Commencement Date will
occur on or about September 18, 2000 (the "Anticipated Commencement Date ") and
the Phase II Completion Date will occur on or about January 1, 2001 (the
"Anticipated Phase II Completion Date "). Landlord shall incur no liability to
Tenant, and this Lease shall not be rendered void or voidable, if for any reason
(i) the Lease Commencement Date has not occurred on or before the Anticipated
Lease Commencement Date, (ii) the Phase II Completion Date has not occurred on
or before the Anticipated Phase II Completion Date, (iii) the Phase I Delivery
Date has not occurred on or before the Anticipated Phase I Delivery Date, or
(iii) the Phase II Delivery Date has not occurred on or before the Anticipated
Phase II Delivery Date.  Landlord shall provide Tenant with notice upon
substantial completion of each Phase of the Building Improvements on the
Premises.   Following receipt of such notice, the representatives of Landlord
and Tenant shall jointly inspect the Premises with Landlord's Architect and, at
Tenant's option, Tenant's Architect, to confirm which items of Building
Improvements for the Building Complex on the punchlist created pursuant to
Section 2.5 have not been completed, distinguishing between those items which
must be completed prior to the Phase of the Premises being deemed substantially
completed and other incomplete items that are not required for such portion of
the Premises to be deemed substantially completed. In the event of a dispute,
Landlord's Architect and Tenant's Architect shall mutually resolve such dispute
and if the Architects cannot agree upon a resolution, the Architects shall
jointly appoint an independent architect whose determination shall be binding on
the parties.  Landlord and Tenant shall  share equally the cost of any required
neutral independent architect.  Upon the request of either party, promptly after
each of the Phase 1 Early Delivery Date, Phase I Delivery Date, Phase II
Delivery Date, Commencement Date, and Phase II Completion Date are each
ascertained, Landlord and Tenant shall execute a certificate (the "Certificate")
setting forth the applicable date and the other information set forth therein.
The form of such Certificate is attached hereto as Exhibit D-1, and is made a
                                                   -----------
part hereof.  Any failure of the parties to execute such Certificate shall not
affect the validity of the applicable date as determined in accordance with this
Article.

          3.5    Tenant and Tenant's Contractors shall be allowed access to
each Phase of the Premises approximately 15 days prior to substantial completion
of the Building Improvements for such Phase to install communications equipment
and other special equipment, fixtures and furniture (to the extent not included
in Tenant Work), and such installations shall not be considered the commencement
of use of the Premises for normal conduct of Tenant's business.  Notwithstanding
the foregoing to the contrary, Tenant may install the wiring of
telecommunications and data equipment at any time after the applicable Delivery
Date.  Any and all installations and other related activity by Tenant or its
contractors prior to the Commencement Date or Phase II Completion Date shall be
coordinated with Landlord and its general contractor to insure that Tenant's
work in and to any portion of the Premises does not interfere with the work
being performed by Landlord and its contractors.

                                       5
<PAGE>

21.  Allowance.

     4.1    Landlord will pay the cost of the Tenant Work completed in
accordance with the Final Working Drawings calculated on the basis of $27.50 per
rentable square foot of the Premises (the "Allowance "). Landlord shall make
progress payments on a monthly basis as portions of the Tenant Work are
completed in accordance with Section 4.1. Tenant Work Costs in excess of the
Finish Allowance ("Excess Costs ") will be at Tenant's sole cost and expense.

     4.2    The Allowance is to be expended solely for the benefit of Landlord;
that is, the Allowance will be expended only to pay for design, engineering,
installation, and construction of the Tenant Work which under the Lease becomes
the property of Landlord upon installation and not for movable furniture,
equipment, and trade fixtures not physically attached to the Premises; provided,
however, Tenant shall have the right to use up to $5.00 per rentable square foot
of the Allowance for cabling and wiring costs, move related expenses, and
Tenants fixtures and furniture. Any of Landlord's costs and expenses payable to
Landlord, required to be paid by Tenant under this Work Letter will also be paid
out of the Allowance. Prior to Tenant commencing construction of the Tenant
Work, Tenant shall  provide Landlord with notice of the total estimated cost of
all Tenant Work.  As design, engineering, and construction work is completed and
Tenant receives invoices therefor, Tenant will submit requests for payment to
Landlord not more frequently than monthly, along with appropriate lien waivers
(substantially in the forms attached hereto as Exhibit 3) and such other
documentation as Landlord requires.  On a monthly basis following receipt of
such documentation (with such payment being made by the 30th of the month if all
required documentation is received by Landlord by the 5th of such month),
Landlord will pay the amounts requested by delivery to Tenant of Landlord's
check(s) payable to Tenant or, at Tenant's option, payable to Tenant and
Tenant's Contractors jointly.  Unless otherwise agreed by Landlord and Tenant in
writing and subject to delays beyond Tenant's reasonable control, if any portion
of the costs to be reimbursed by the Allowance has not been requested by Tenant
or will be requested for Tenant Work that is ongoing as of September 1, 2001
such amounts shall be forfeited by Tenant.

     4.3    Landlord shall, during completion of the Tenant Work and immediately
thereafter, reasonably cooperate in the balancing of the Building HVAC system
serving the Premises.  Landlord shall pay for costs of balancing the Building
Improvements portions of the HVAC system and Tenant shall pay for balancing the
portions of the system within the Premises.

     4.4    Subject to the mutual waiver in Section 18.6 of the Lease, Tenant
will indemnify, defend and hold harmless Landlord, Building Manager, and
Landlord's Contractors from and against liability, costs or expenses in
accordance with Section 16.1 of the Lease. Subject to the mutual waiver in
Section 18.6 of the Lease, Landlord will indemnify, defend and hold harmless
Tenant and Tenant's Contractors from and against liability, costs or expenses in
accordance with Section 16.3 of the Lease. Tenant will also repair or cause to
be repaired at its expense all damage caused to the Premises or the Building by
Tenant's Contractors or its subcontractor, subject to the mutual waiver in
Section 18.6 of the Lease and the provisions for Builder's Risk insurance
provided in this Work Letter and Exhibits. Further, Landlord will have the right
as described in Section 12.1 of the Lease to post and maintain notices of non-
liability.

     4.5    Tenant agrees to submit to Landlord upon completion of all work one
reverse mylar sepia and two blueprint copies of the record or as-built drawings
(the Final Working Drawings showing all changes thereon).  However, Landlord's
use of such drawings shall be subject to Tenant's or Tenant's contractors', or
agents' of either's common law and statutory ownership rights in said drawings.

     4.6    Notwithstanding any provision herein or in the Lease to the contrary
and in accordance with Sections 3.1 and 3.2 above, the Commencement Date (and,
as applicable, the Phase II Completion Date) and Tenant's Rent obligations and
other obligations will not be delayed or extended by any delay in completion of
the Tenant Work unless such delay is caused by Net Landlord Delay.  The term
"Landlord Delay " means any delay in the preparation, finalization or approval
of the Approved Space Plans (to the extent provided in Section 1.3), Final
Working Drawings or completion of the Tenant Work caused by Landlord's failure
to perform its obligations under this Work Letter within the time limits set
forth herein or as a result of interference caused by Landlord or Landlord's
Contractor (to the extent not permitted herein); Tenant Delay shall not be
considered Landlord Delay. Tenant shall provide notice to Landlord as soon as
Tenant determines that Landlord Delay has occurred.  All delays other than
Landlord Delay or Force Majeure are deemed "Tenant Delay ."  "Force Majeure "
means delay in the performance of any acts required under this Lease by reason
of labor strikes, lockouts, failure of power, inclement weather of such severity
as to preclude continued work under prevailing industry standards, riots,
insurrection, war, inability to procure materials, default of the other party
hereto, or any other reason of a like nature which is beyond the reasonable
control of the party so delayed.  "Net Landlord Delay " means the number of
days, if any, by which Landlord Delay exceeds Tenant Delay (to the extent both
impact the same discrete timing issue), and the Commencement Date and/or Phase
II Completion Date, as applicable, will be delayed by a number of days equal to
the number of days of Net Landlord Delay, if any, in accordance with Sections
3.1 and 3.2 above.
<PAGE>

     4.7    Tenant designates and authorizes Pat Marinaro to act for Tenant in
this Work Letter.  Tenant has the right by written notice to Landlord to change
its designated representative.

     4.8    Landlord designates and authorizes George Chelwick to act for
Landlord in this Work Letter. Landlord has the right by written notice to Tenant
to change its designated representative.

     4.9    All notices required hereunder will be in writing in accordance with
Section 28 of the Lease. Whenever Tenant's or Landlord's approval or consent is
required under the express terms of this Work Letter, such approval or consent
shall not be unreasonably withheld, conditioned or delayed.
<PAGE>

                LIST OF EXHIBITS
                ----------------

Exhibit 1       Space Plan and Drawings
                Requirements
Exhibit 2       Landlord's Requirements of Tenant
                the Contractors
Exhibit 3       Form of Lien Waivers
Exhibit 4       Landlord's Drawings
Exhibit 5       Building Improvements
Exhibit 6       Schedule of Dates
Exhibit 7       Tenant Work Issues
<PAGE>

                            EXHIBIT 1 TO WORK LETTER
                            ------------------------

              SPACE PLANS AND ARCHITECTURAL DRAWINGS REQUIREMENTS

I.   Space Plans
     -----------

     Tenant's Space Plans will comply with the following requirements which are
     intended to assist Tenant and Tenant's Architect in defining all
     information required for Landlord's review of the space usages and
     evaluation of the improvements contemplated thereby.

     1. All Space Plans will be drawn to 1/8" scale and may be produced on
        CAD equipment.

     2. Tenant will submit one reverse mylar sepia and two blue prints of
        all Space Plans with notes describing the general intent of the
        usage and the improvement requirements.

     3. The Space Plans and notes will include:  (a) partition layout and
        door locations; (b) reflected ceiling plan showing non-standard
        lighting and ceiling construction or constraints which will affect
        mechanical, electrical, fire protection or life safety systems
        (see Exhibit 5) ; (c) general location for major floor
        penetrations, including but not limited to special stairs,
        dumbwaiters, conveyors, pneumatic systems, elevators or
        architectural features; and (d) general description, size and
        proposed location of any equipment anticipated to be located
        outside the Premises (including rooftop antennas, ground mounted
        generators and similar requirements).

II.  Architectural and Engineering Working Drawings

Tenant's submission of Architectural Working Drawings and Engineering Working
Drawings (collectively the "Working Drawings ") shall include one reverse mylar
and two blueprints of Architectural Drawings and Specifications to Landlord and
comply with the following requirements which are intended to assist Tenant,
Tenant's Architect and Tenant's Engineer in defining all information required by
Landlord to complete Landlord's review of space usages and the quality and
extent of the proposed construction and its effect upon the Building
Improvements.

The Working Drawings will depict the quality of Tenant Work to be performed and
must provide for a quality level equal to (as reasonably determined by Landlord)
or exceeding the requirements of the Building Improvements, consistent with
similar Class "A" office space located in northern Virginia.

The Architectural Working Drawings and Engineering Working Drawings collectively
will include but not be limited to:  (a) partition layout and door locations;
(b) electrical outlets, including the locations and panel schedules; (c)
telephone outlets, including designation of type of switch or equipment and
notes regarding conduit sizing to each outlet, power and mechanical requirements
for system and any requirements affecting base building construction, including
modifications required to floor or main telephone rooms; (d) reflected ceiling
plan showing standard and non-standard lighting, switching requirements and
ceiling construction or constraints which will affect mechanical, electrical,
fire protection or life safety systems, and will include all necessary
specifications and details of items or construction; (e) Tenant's occupancy
capacity, usage equipment loads for all spaces, particularly special usage
rooms, including but not limited to conference rooms, lounges, coffee rooms,
copy rooms, computer terminal or keypunch rooms, audio-visual rooms and
reproduction or print rooms which require special heating, ventilating, air
conditioning or fire protection (all specifications on usage or equipment
therein, including a summary of BTU per hour output of all equipment and
parameters as to extent of any special work required); (f) Tenant's floor
loading for above standard floor loading areas (all specifications, weight,
vibration and vibration isolation for each item sufficiently complete for
structural engineering design), particularly special usage rooms, including, but
not limited to file rooms, storage rooms, computer rooms and reproduction or
print rooms; (g) floor and ceiling penetrations, including but not limited to
special stairs, dumbwaiters, conveyors, skylights (if approved), pneumatic
systems, elevators or architectural features; and (h) all structural,
mechanical, electrical, fire protection, controls and life safety systems
requirements.

The Working Drawings will include the following as well:  (1) all millwork and
equipment which will be part of the Tenant Work and become part of the Premises;
(2) complete finish designations for all floors, walls, ceilings, including
millwork, door frames, etc.; (3) keying schedules; (4) special blocking
requirements as may be required to support wall or ceiling hung furniture or
equipment; and (5) all other information necessary to complete construction of
the Premises, including the architect's and engineer's stamps if required by any
applicable State or local law or otherwise required to permit construction under
such law or applicable regulations.
<PAGE>

                            EXHIBIT 2 TO WORK LETTER
                            ------------------------

                     LANDLORD REQUIREMENTS OF THE CONTRACT

The Contract will be subject to review and approval of Landlord in accordance
with the Work Letter and will fully incorporate the following provisions.  In
the event of any conflict between any provisions of the Contract and the
provisions below, the provisions below will control.

1.       The Contract will be in writing and will cover all aspects of the
         Tenant Work.  No Tenant Work will be performed except pursuant to the
         Contract.  Fully executed copies of the Contract will be delivered to
         Landlord.  Following delivery of a copy of the Contract to Landlord and
         its approval (or deemed approval), no material modification will be
         effective unless and until a copy thereof has been delivered to
         Landlord for its review; provided, however, change orders which do not
         modify the basic terms and provisions of the Contract will not require
         review by Landlord except as noted below.

2.       Changes in the Final Working Drawings will be made only upon prior
         written approval (or deemed approval) of Landlord (to the extent
         required under and in accordance with Section 1.5 of the Work Letter).

3.       Scheduling of Tenant Work:  The Contract will obligate Tenant's
         Contractor to perform Tenant Work in accordance with time schedules
         acceptable to Tenant, Tenant's Contractor and Landlord (which approval
         shall be based on consistency with Landlord's schedule for completion
         of the Building Improvements).  Any schedule proposed by Tenant's
         Contractor will be based upon Tenant's Contractor applying its best
         efforts to the Tenant Work.

4.       Tenant's Contractor will not knowingly perform Tenant Work inconsistent
         with the Final Working Drawings which will result in a lesser quality
         installation or provide inferior performance than that established by
         the base shell and core drawings and specifications covering similar
         work items.  Landlord will have the right at any time during the
         performance of Tenant Work or thereafter to require replacement and
         reconstruction at Tenant's Expense of Tenant Work not conforming to the
         standards and specifications in the Final Working Drawings.

5.       Tenant and Tenant's Contractor will give all notices and comply with
         all laws, ordinances, rules, regulations and orders of any public
         authority relating to the performance of the Tenant Work.  If either
         party observes that any Tenant Work is at variance with any applicable
         codes, ordinances, laws, rules and regulations (collectively,
         "Applicable Laws "), it will promptly notify the other party and
         Landlord in writing, and necessary changes will be made by Tenant.  If
         Tenant's Contractor performs any Tenant Work that it knows is contrary
         to Applicable Laws, and fails to deliver prior notice to Tenant and
         Landlord, Tenant's Contractor will assume full responsibility therefor
         and will bear all costs attributable to repair, replacement or
         correction.  Tenant, Tenant's Contractor and its subcontractors will
         comply with Federal, State and local tax laws, social security acts,
         unemployment compensation acts and such other acts and laws as are
         applicable to the performance of Tenant Work.

6.       All risk of loss to all property of Tenant, Tenant's Contractor and its
         subcontractors will be the sole responsibility of Tenant, Tenant's
         Contractor and its subcontractors, and Landlord will have no
         responsibility therefor, subject to Builder's Risk insurance on the
         Tenant Work to the extent carried by Landlord in accordance with
         Section 2.16 of the Work Letter.

7.       The following insurance requirements will be complied with:

         a.   Minimum Coverage - Prior to any Tenant Work being commenced by
              ----------------
              Tenant's Contractor, it will obtain and maintain insurance with
              minimum coverage and limits to protect Tenant and Landlord from
              the claims hereafter set forth which may arise or result from
              Tenant's Contractor's performance of any Tenant Work, whether such
              work is performed by Tenant's Contractor, its subcontractors, or
              by anyone for whose acts such parties
<PAGE>

              may be liable as follows (subject to the provisions below, such
              limits may be provided by an appropriate "umbrella" policy):

         (1) Workmen's Compensation and occupational disease insurance at
             the statutory limits provided for by the State in which the
             Premises are located;

         (2) Employer's liability insurance in an amount not less than
             $100,000 for all damages arising from each accident or
             occupational disease;

         (3) Commercial general liability insurance covering:

             (i)    Operations premises liability;

             (ii)   Owner's and Contractor's protective liability;

             (iii)  Completed operations;

             (iv)   Product liability;

             (v)    Contractual liability;

             (vi)   Broad form property damage endorsement and property damage
             caused by conditions otherwise subject to exclusion for
             explosion, collapse or underground damage;

             (vii)  Architect's and engineer's professional liability insurance
             (for Tenant's Architect and Tenant's Engineer)

         (4) Insurance limits:

             Bodily Injury:
             -------------

             $1,000,000 each occurrence; $1,000,000 aggregate completed
             operations products

             Property Damage
             ---------------

             $500,000 each occurrence; $500,000 aggregate operations; $500,000
             aggregate protective; $500,000 aggregate completed operations
             products

         (5) Comprehensive automobile liability insurance covering all
             owned, hired or non-owned vehicles including the loading and
             unloading thereof with limits of no less than:

             Automobile Bodily Injury:
             ------------------------

             $500,000 each person; $1,000,000 each occurrence;

             Automobile Property Damage:
             --------------------------

             $500,000 each person

        b.    Unless Landlord retains Builder's Risk insurance on the Tenant
              Work in accordance with Section 2.16 of the Work Letter, Tenant or
              Tenant's general contractor shall carry Builder's Risk insurance
              covering the completed value of the Tenant Work which will afford
              coverage against "all risks" for physical loss or damage.

        c.    Cancellation - All such insurance will be carried with a company
              ------------
              reasonably satisfactory to Landlord and Tenant and the liability
              policy will name Landlord and
<PAGE>

              Tenant and their employees and agents as additional insured
              parties. Each policy will provide that it will not be cancelled
              or altered except after 15 days prior written notice to Tenant
              and Landlord, and the certificate of insurance will so state.

        d.    Policy Termination - Tenant's Contractor and each subcontractor
              ------------------
              will maintain all insurance required hereunder during the term of
              the Contract and for a period ending one year after the date of
              completion of all Tenant Work done pursuant to the Contract to the
              extent such insurance is written in a "claims made basis."

        e.    Policies - Prior to commencement of work by Tenant's Contractor,
              --------
              it will deliver one copy of the policies or certificates
              evidencing such insurance to Tenant and Landlord.  Such policies
              must be approved by Tenant and Landlord prior to commencement of
              work.  Without the written consent of Landlord, Tenant's
              Contractor agrees that it will not allow any subcontractor to
              commence work within the building until such subcontractor has
              obtained the required insurance.

        f.    Umbrella Liability Insurance - Umbrella liability insurance with
              ----------------------------
              limits of liability for claims of bodily injury, personal injury
              and property damage liability not less than $10,000,000 each
              occurrence and $10,000,000 aggregate.

        g.    Waiver of Subrogation - Landlord, Tenant and Tenant's Contractor
              ---------------------
              will waive all rights against each other, and their respective
              contractors, subcontractors and sub-subcontractors, agents and
              employees, for damages caused by fire or other perils covered
              under the Builder's Risk insurance policy on the Tenant Work.

9.       Tenant's Contractor will indemnify, defend, and hold harmless Tenant
         and Landlord and their respective representatives, agents and employees
         from and against all claims, damages, losses and expenses, including,
         but not limited to reasonable attorney's fees, arising out of or
         resulting from the performance of Tenant Work or Tenant's Contractor's
         failure to perform in accordance with the Contract (but specifically
         excluding the Tenant Work itself and the Building) which are:  a)
         caused in whole or in part by any negligent act or omission of Tenant's
         Contractor, any subcontractor, anyone directly or indirectly employed
         by any of them or anyone for whose acts any of them may be liable,
         regardless of whether or not such claim, loss, damage or expense is
         caused in part by a party indemnified hereunder, and b) attributable to
         bodily injury, sickness, disease or death, or destruction of or damage
         to tangible property including loss of use resulting from any of the
         foregoing acts.

         Tenant's Contractor's indemnification obligation under this Paragraph 9
         will not be limited by any limitation on the amount or type of damages,
         compensation or benefits payable by or for the Contractor or any
         subcontractor under workmen's compensation acts, disability benefit
         acts or other employee benefit acts.

10.      Landlord or Tenant may require Tenant's Contractor to provide payment
         and performance bonds for any Tenant Work being completed by
         subcontractors other than subcontractors that are also subcontractors
         or contractors to Landlord, such bonds to be provided at Tenant's
         expense (subject to reimbursement under the Allowance).  Any bond will
         be requested and provided prior to commencement of Tenant Work.

11.      If Tenant's Contractor is adjudicated a bankrupt, or makes a general
         assignment for the benefit of its creditors, or if a receiver is
         appointed on account of Tenant's Contractor's insolvency, or if
         Tenant's Contractor persistently or repeatedly refuses or fails, except
         in cases where delay is justified, to supply enough properly skilled
         workmen or proper materials or if Tenant's Contractor materially
         disregards Applicable Laws, or otherwise is guilty of a material
         violation of a provision of the Contract, Tenant may, without prejudice
         to any right or remedy and after giving Tenant's Contractor and its
         surety, if any, 7 business days' written notice, terminate the Contract
         and take possession of all materials, equipment, tools, construction
         equipment and machinery  owned by Tenant's Contractor and will
         thereafter complete the Tenant Work by whatever method it may
<PAGE>

         deem expedient. In such case, Tenant's Contractor will not be entitled
         to receive any further payments until completion of all Tenant Work;
         provided, however, that Tenant's actions will not release Tenant's
         Contractor from any obligations to Tenant arising from its performance
         or nonperformance prior to the date of such termination. Following
         completion, Tenant will pay Tenant's Contractor an amount equal to the
         aggregate of the amounts actually due under the Contract at the time of
         the termination, less the cost to Tenant of completing the Tenant Work.

12.      Prior to commencement of any Tenant Work in the Premises, Tenant will
         give written notice to Landlord of the date work will commence. If a
         subcontractor or materialman files a mechanics' lien as a result of
         performing Tenant Work pursuant to the Contract, then, provided
         Tenant's Contractor has been paid for such work, Tenant's Contractor
         will indemnify and defend Tenant and Landlord from said lien and will,
         when requested by Tenant or Landlord, furnish (as Landlord or Tenant
         may specify) either a bond sufficient to discharge the lien, deposit in
         an escrow approved by Landlord and Tenant a sum equal to 150% of the
         amount of such lien or obtain for Landlord an endorsement through
         Landlord's title policy insuring against loss or damage resulting from
         such lien.  Subject to any restrictions of Landlord's Mortgagee on the
         Building, Tenant's Contractor may, in cooperation with Landlord and
         Tenant, contest the validity of a mechanics' lien, including the right
         to prosecute any appeals so long as during the pendency of any contest,
         Tenant's Contractor will effectively stay any official or judicial sale
         of the Building, upon execution or otherwise, and so long as Tenant's
         Contractor immediately pays any final judgment entered and procures
         record satisfaction thereof.  If Tenant or Landlord is a party to any
         such contest, or any other action resulting from or arising out of the
         performance of the Tenant Work, Tenant's Contractor will pay all legal
         fees and other costs and expenses incurred by Landlord and Tenant in
         such action.  If Tenant's Contractor fails to provide a bond, cash
         escrow or title endorsement, or otherwise fails to fully satisfy and
         obtain the release of a lien in accordance with the provisions hereof,
         Tenant's Contractor will be obligated to refund Tenant or Landlord, as
         the case may be, all monies that the latter may pay in discharging any
         such lien including costs and reasonable attorneys' fees incurred in
         settling, defending against, appealing or in any other manner dealing
         with any such lien.

13.      Tenant's Contractor will warrant and agree at its expense to correct or
         cause to be corrected any defects in the Tenant Work (including, but
         not limited to, defects due to defective workmanship or materials
         whether supplied, installed or performed by Tenant's Contractor or any
         subcontractor or supplier) which occur within one year after Tenant's
         Contractor has substantially completed the Tenant Work, including
         completion of all punchlist items, or for such longer period as may be
         set forth in the Final Working Drawings.  Tenant's Contractor will
         require a similar warranty in all subcontracts, and will deliver to
         Landlord and Tenant, together with appropriate assignments, if
         required, all warranties of subcontractors and suppliers.  All
         warranties will extend to both Landlord and Tenant, as their respective
         interests in such Tenant Work exist pursuant to the Lease.

14.      Tenant's Contractor will:  (a) comply with all reasonable rules
         relating to construction activities in the Building promulgated by
         Landlord or Landlord's Contractor; (b) be responsible for reaching
         agreement with Landlord as to the reasonable conditions for use of the
         elevators, systems interfacing, use of temporary utilities, access to
         the Premises and use of truck docks and storage areas (all of which
         shall be without charge to Tenant by Landlord).

15.      Landlord shall make available systems interfacing and use of temporary
         utilities as is customary in construction of similar buildings in the
         suburban Washington, D.C. area, subject to Landlord's schedule for
         completion of the Building Improvements. Tenant and Tenant's
         contractors shall arrange for their own hoisting of materials.
         Landlord shall have no obligation to provide hoisting facilities or
         permit use of the Building elevators for such purposes; provided,
         however, to the extent one of the Building elevators is operating,
         Tenant shall have the right to non-exclusive use of such elevator.

16.      Landlord and Landlord's Contractor may, from time to time, inspect or
         perform work within the Premises, subject to the provisions of the Work
         Letter.  Such inspections or work will not unreasonably conflict with
         Tenant's Contractor's work.  Landlord may suspend
<PAGE>

         Tenant's Contractor's work in the Premises if such work, in the
         reasonable opinion of Landlord, presents a danger to life, safety, or
         property, or in an emergency situation. Landlord and/or Landlord's
         Contractor shall coordinate such work with Tenant and Tenant's
         Contractor to minimize any conflict or delay with Tenant Work.

17.      Tenant will give Landlord reasonable prior notice of all inspections,
         punchouts and other reviews during the course of construction so that
         Landlord may observe such events; such notice shall be deemed given by
         notes of such scheduled events given at weekly meetings and appearing
         in minutes of such weekly meetings.  Landlord will be likewise informed
         of all Building Department inspections and requirements for issuance of
         the Certificate of Occupancy for the Premises.  Landlord will also be
         informed in advance of weekly construction meetings and may attend such
         meetings. Key construction events shall be recorded in minutes of such
         meetings. Landlord's observation of any such events will, in no event
         be construed or interpreted as a review or approval by Landlord of any
         such work nor will it prevent Landlord, if it thereafter discovers any
         deficiency in such Work, from requiring correction.  Tenant's
         Contractor will be solely responsible for obtaining a certificate of
         occupancy (or its equivalent) for the Premises (as distinguished from a
         similar certificate to the extent required for the Building
         Improvements) and will submit to Landlord the original prior to
         Tenant's occupancy of the Premises for the purpose of conducting
         business.

18.      Landlord will have the option of reviewing in the field/as installed
         all equipment and materials to be used in the construction of the
         Tenant Work for consistency with Final Working Drawings and all work
         prior to Tenant move-in.  Such review will in no event constitute
         approval by Landlord and Landlord shall use reasonable efforts to
         minimize any delay arising from such reviews.
19.      Tenant will promptly furnish Landlord a copy of the building permit
         issued to Tenant's Contractor after issuance.

20.      Tenant's Contractor will not store materials or supplies in or outside
         the Building (other than within the Premises) without the prior
         approval of Landlord or Landlord's Contractor, which shall not be
         unreasonably withheld.

21.      All deliveries except hand-held items must be taken to the floors via
         elevator(s) designated by Landlord for such purpose.

22.      Tenant's Contractor will provide at all times direct supervision of all
         work being performed for Tenant.

23.      Tenant's Contractor will cooperate with Landlord in disposing refuse
         resulting from the Tenant Work.  This may include the use of Landlord's
         dumpster and a proration of charges associated with such use or at
         Landlord's option at Tenant's expense the placement of Tenant
         Contractor's dumpster at a location reasonably specified by Landlord.

24.      Tenant's Contractor will acknowledge that the work to be performed by
         it for Tenant is also for the direct benefit of Landlord.  Landlord
         will have the right to pursue in its own name directly against Tenant's
         Contractor any rights or remedies including, without limitation, claims
         for damages granted to Tenant.
<PAGE>

                            EXHIBIT 3 TO WORK LETTER
                            ------------------------

                              FORM OF LIEN WAIVERS

Appropriate lien waivers substantially in the forms attached hereto (with blanks
completed and notary revised as appropriate) as Exhibits 3-1, 3-2, 3-3, and 3-4,
as the case may be, will accompany all requests for payment by Tenant.
<PAGE>

                           EXHIBIT 3-1 TO WORK LETTER
                           --------------------------

STATE OF ___________  )        INTERIM CONTRACTOR'S AFFIDAVIT
                      ) ss.    RELEASE AND LIEN WAIVER
COUNTY OF __________  )

TO WHOM IT MAY CONCERN:

    The undersigned, being first duly sworn, deposes and says that:

    1.    He is _______________ of the ________________________, who is the
general Contractor for the project hereinafter identified (the "Contractor "),
and that the undersigned is authorized to execute and deliver this document on
behalf of the Contractor.

    2.    The Contractor is the contractor for the performance of certain work
and/or the furnishing of certain materials or supplies (the "Work ") pursuant to
a Contract between Contractor and _______________________________, as Owner, for
the improvements and project commonly known as
__________________________________________ (the "Project ") upon property
legally described as:  ____________________________________________, County of
_______________, State of _______________, hereinafter referred to as the
"Property ."

    3.    This instrument is executed and delivered in consideration of and for
the purpose of inducing _________________________ ("Construction Lender ") and
the Owner to make an interim payment of $__________ under the Contract, subject
to collection of any check given as payment.  The total amount of the Contract
including change orders is $__________, and the undersigned acknowledges that
upon receipt of this interim payment, the Contractor has received interim
payments totalling $__________ under the Contract.

    4.    The undersigned for the Contractor, subject to the receipt and
collection of the interim payment herein requested, warrants and represents
that:  (i) all materials delivered to said project by or for the Contractor are
for use therein only; (ii) title to all work, materials and equipment covered by
said payment, whether or not incorporated in the improvement on the Property,
has passed to the Owner, free and clear of all liens, claims, security or
encumbrances (hereinafter all referred to as "liens"); (iii) all taxes
applicable to the materials furnished for use in or on the Property and all
taxes for the Work performed under the Contract have been fully paid; and (iv)
all laborers, mechanics, subcontractors, materialmen and suppliers for all work
done and for all materials, machinery, equipment, fixtures, tools, scaffolding
and appliances furnished for the performance of the Contract and for any other
indebtedness connected therewith for which the Owner of the Property might be
responsible have been paid in full to the date hereof.  Contractor, to the
extent of the total of interim payments received, for itself, its successors,
and on behalf of all persons able to claim through or under the Contractor:  (a)
waives, relinquishes and releases all liens and rights of claims to liens for
labor or materials furnished in the construction, improvement, alteration or
repair involved in performance under the Contract; (b) agrees (1) to save Owner
and Construction Lender harmless from all liability, costs and expenses,
including reasonable attorneys' fees, resulting from mechanic's and/or
materialmen's liens for the performance of work or the furnishing of materials
or supplies pursuant to the Contract, (2) to discharge (by bond or otherwise) or
to defend suit to enforce any mechanic's or materialmen's lien, claim to or
right of action for any such lien which may be filed, and (3) to satisfy any
claims or demands which arise out of, which are due to or which may be made for,
any work performed or supplies furnished under the Contract or in furtherance of
the construction or completion of the Contract, whether directly or indirectly
attributable to the Contract; and (c) hereby releases the present and any future
Owner of the Property, the Property, the Construction Lender and any lender who
may now or hereafter have a security interest in the Property, from all claims,
rights of action, liabilities and liens which may be filed or asserted in
connection with the Contract.

    Dated this _____ day of _______________, 2000.

                              Authorized representative of Contractor

    SUBSCRIBED AND SWORN TO before me this _____ day of __________________,
2000.

    My commission expires ________________________.

<PAGE>

                              Notary Public
<PAGE>

                           EXHIBIT 3-2 TO WORK LETTER
                           --------------------------

STATE OF __________ )
                    )         FINAL CONTRACTOR'S AFFIDAVIT,
COUNTY OF ________  )         RELEASE AND LIEN WAIVER

TO WHOM IT MAY CONCERN:

    The undersigned, being first duly sworn, deposes and says that:

    1.    He is __________________ of the _____________________, who is the
general Contractor for the project hereinafter identified (the "Contractor"),
and that the undersigned is authorized to execute and deliver this document on
behalf of the Contractor.

    2.    The Contractor is the contractor for the performance of certain work
and/or the furnishing of certain materials or supplies (the "Work") pursuant to
a Contract between Contractor and ____________________, as Owner, for the
improvements and project commonly known as __________________________
________________________ (the "Project") upon property legally described as:
_________________________________, County of __________, State of __________,
hereinafter referred to as the "Property."

    3.    This instrument is executed and delivered in consideration of and for
the purpose of inducing _________________________ ("Construction Lender") and
the Owner to make final payment of $__________ under the Contract, subject to
collection of any check given as payment.  The total amount of the Contract
including change orders is $__________, and the undersigned acknowledges that
upon receipt of this final payment, the Contractor has been paid in full the
total contract price under the Contract.

    4.    The undersigned for the Contractor, subject to the receipt and
collection of the final payment herein requested, warrants and represents that:
(i) all materials delivered to said project by or for the Contractor are for use
therein only; (ii) title to all work, materials and equipment covered by said
payment, whether or not incorporated in the improvement on the Property, has
passed to the Owner, free and clear of all liens, claims, security or
encumbrances (hereinafter all referred to as "liens"); (iii) all taxes
applicable to the materials furnished for use in or on the Property and all
taxes for the Work performed under the Contract have been fully paid; and (iv)
all laborers, mechanics, subcontractors, materialmen and suppliers for all work
done and for all materials, machinery, equipment, fixtures, tools, scaffolding
and appliances furnished for the performance of the Contract and for any other
indebtedness connected therewith for which the Owner of the Property might be
responsible have been paid in full.  Contractor for itself, its successors, and
on behalf of all persons able to claim through or under the Contractor:  (a)
waives, relinquishes and releases all liens and rights of claims to liens for
labor or materials furnished in the construction, improvement, alteration or
repair involved in performance under the Contract; (b) agrees (1) to save Owner
and Construction Lender harmless from all liability, costs and expenses,
including reasonable attorneys' fees, resulting from mechanic's and/or
materialmen's liens for the performance of work or the furnishing of materials
or supplies pursuant to the Contract, (2) to discharge (by bond or otherwise) or
to defend suit to enforce any mechanic's or materialmen's lien, claim to or
right of action for any such lien which may be filed, and (3) to satisfy any
claims or demands which arise out of, which are due to or which may be made for,
any work performed or supplies furnished under the Contract or in furtherance of
the construction or completion of the Contract, whether directly or indirectly
attributable to the Contract; and (c) hereby releases the present and any future
Owner of the Property, the Property, the Construction Lender and any lender who
may now or hereafter have a security interest in the Property, from all claims,
rights of action, liabilities and liens which may be filed or asserted in
connection with the Contract.

    Dated this _____ day of _______________, 2000.

                              Authorized representative of Contractor

    SUBSCRIBED AND SWORN TO before me this _____ day of __________________,
2000.

    My commission expires _______________________.
<PAGE>

                              Notary Public
<PAGE>

                           EXHIBIT 3-3 TO WORK LETTER
                           --------------------------

                Project                      INTERIM SUBCONTRACTOR'S OR

                Job Address                  MATERIAL SUPPLIER'S AFFIDAVIT,

                Job Number                   RELEASE AND LIEN WAIVER

STATE OF _________  )
                        ) ss.
COUNTY OF ____________  )

     The undersigned subcontractor or material supplier (herein referred to as
"Subcontractor "), being first duly sworn, deposes and says that:  He is over
the age of 21 years and resides at:
_________________________________________________________________.

(IF SUBCONTRACTOR IS AN INDIVIDUAL:)

     1.   He is the Subcontractor referred to herein.

(IF SUBCONTRACTOR IS A PARTNERSHIP:)

     1.   He is a general partner in _____________________________________, a
co-partnership composed of the undersigned and carrying on business at
_______________________________, City of ___________.  Said co-partnership is
the Subcontractor referred to herein.

(IF SUBCONTRACTOR IS A CORPORATION:)

     1.   He holds the title of _______________, in _______________________, a
corporation organized under the laws of the State of ____________, carrying on
business at ________________________________________, City of ____________,
State of _________________, which corporation is the Subcontractor referred to
herein.  The undersigned is authorized to execute this instrument on its behalf.

     2.   Subcontractor is a subcontractor or material supplier for the
performance of certain work and/or the furnishing of certain materials or
supplies pursuant to an agreement or purchase order, as the case may be
(hereinafter called the "Subcontract," which term will refer to the agreement or
purchase order, as the case may be), under a general contract between
_________________________________ (hereinafter called "Contractor"), and
________________________________ (hereinafter called the "Owner"), for the
improvements or project known as ______________________________, at
_________________________, City of ____________, County of ____________, State
of ____________ (hereinafter called the "Property").

     3.   This instrument is delivered in consideration of and for the purpose
of inducing Contractor to make interim payment of $__________ under the
Subcontract, subject to collection of any check given as payment.  Subcontractor
acknowledges that upon receipt of this interim payment, Subcontractor has
received from Contractor interim payments totaling $__________ under the
Subcontract.
<PAGE>

     4.   Subcontractor warrants and represents that:  (i) all materials
delivered to said project by or for Subcontractor are for use therein only; (ii)
title to all work, material and equipment covered by said payment, whether or
not incorporated in the Property, has passed to the Owner, free and clear of all
liens, claims, security interests or encumbrances (hereinafter all referred to
as "liens"); (iii) all taxes applicable to the materials furnished and the work
performed under the Subcontract have been fully paid; and (iv) all laborers,
mechanics, sub-subcontractors, materialmen and suppliers for all work done and
for all materials, machinery, equipment, fixtures, tools, scaffolding and
appliances furnished for the performance of the Subcontract and for any other
indebtedness connected therewith for which the Owner of the Property might be
responsible have been paid in full to the date hereof.  Subcontractor, to the
extent of the total of interim payments received, for itself, its successors,
and on behalf of all persons able to claim through or under Subcontractor:  (a)
waives, relinquishes and releases all liens and right or claim to a lien for
labor or materials furnished in the construction improvement, alteration or
repair involved in performance under the Subcontract; (b) agrees to save
Contractor harmless from all liability, costs and expenses, including reasonable
attorneys' fees, to: (1) discharge (by bond or otherwise) or to defend suit to
enforce, any mechanics' or materialmen's lien, claim to or right of action for
such lien, which may be filed and (2) satisfy any claims or demands arising out
of, due or which may be made, directly or indirectly attributable to the
Subcontract, any work performed or supplies furnished thereunder, or in
furtherance of the construction or completion of the subcontract work; and (c)
hereby releases Contractor, any money earned by Contractor, Contractor's
sureties, the present and any future Owner, the Property and any lender who may
now or hereafter have a security interest therein, from all claim, right of
action, liability and lien which may be filed or asserted in connection with the
Subcontract.

     Dated this _____ day of _______________, 2000.

                            As Subcontractor, General Partner of
                            Subcontractor, or Authorized Officer of
                            Subcontractor, above described

STATE OF ______________  )
                         ) ss.
COUNTY OF _____________  )

     Subscribed and sworn to before me this _____ day of _____________, 2000, by
________________________, known to me to be the above-named signatory, who
personally appeared before me and acknowledged that the foregoing instrument was
freely and voluntarily executed for the uses and purposes and on behalf of the
Subcontractor therein mentioned.

     My commission expires ___________________________.

                                    Notary Public in and for
                                    said County and State
<PAGE>

                           EXHIBIT 3-4 TO WORK LETTER
                           --------------------------

                Project                      FINAL SUBCONTRACTOR'S OR

                Job Address                  MATERIAL SUPPLIER'S AFFIDAVIT,

                Job Number                   RELEASE AND LIEN WAIVER

STATE OF __________ )
                    ) ss.
COUNTY OF ________  )

     The undersigned subcontractor or material supplier (herein referred to as
"Subcontractor"), being first duly sworn, deposes and says that:  He is over the
age of 21 years and resides at:  __________________________________
______________________________.

(IF SUBCONTRACTOR IS AN INDIVIDUAL:)
     1.   He is the Subcontractor referred to herein.

(IF SUBCONTRACTOR IS A PARTNERSHIP:)

     1.   He is a general partner in _____________________________, a co-
partnership composed of the undersigned and carrying on business at
____________________________________________, City of ____________.  Said co-
partnership is the Subcontractor referred to herein.

(IF SUBCONTRACTOR IS A CORPORATION:)

     1.   He holds the title of _______________, in ______________________
____________________, a corporation organized under the laws of the State of
____________, carrying on business at _________________________________, City of
____________, State of ____________, which corporation is the Subcontractor
referred to herein.  The undersigned is authorized to execute this instrument on
its behalf.

     2.   Subcontractor is a subcontractor or material supplier for the
performance of certain work and/or the furnishing of certain materials or
supplies pursuant to an agreement or purchase order, as the case may be
(hereinafter called the "Subcontract," which term will refer to the agreement or
purchase order, as the case may be), under a general contract between
________________________________ (hereinafter called "Contractor"), and
_______________________________________ (hereinafter called the "Owner"), for
the improvements or project known as ________________________ at
_____________________________, City of ____________, County of __________, State
of _____________(hereinafter called the "Property").

     3.   This instrument is delivered in consideration of and for the purpose
of inducing Contractor to make final payment of $__________, subject to
collection of any check given as payment.  Subcontractor acknowledges that upon
receipt of this final payment, Subcontractor has been paid in full the total
subcontract price of $__________, for all of the work performed under the
Subcontract, including retainage, if any.

     4.   Subcontractor warrants and represents that:  (i) all materials
delivered to said project by or for Subcontractor are for use therein only; (ii)
title to all work, material and equipment covered by said payment, whether or
not incorporated in the Property, has passed to the Owner, free and clear of all
liens, claims, security interests or encumbrances (hereinafter all referred to
as "liens"); (iii) all taxes applicable to the materials furnished and the work
performed under the Subcontract have been fully paid; and (iv) all laborers,
mechanics, sub-subcontractors, materialmen and suppliers for all work done and
for all materials, machinery, equipment, fixtures, tools, scaffolding and
appliances furnished for the performance of the Subcontract and for any other
indebtedness connected therewith for which the Owner of the Property might be
responsible have been paid in full. Subcontractor for itself, its
<PAGE>

successors, and on behalf of all persons able to claim through or under
Subcontractor: (a) waives, relinquishes and releases all liens and right or
claim to a lien for labor or materials furnished in the construction
improvement, alteration or repair involved in performance under the Subcontract;
(b) agrees to save Contractor harmless from all liability, costs and expenses,
including reasonable attorneys' fees, to: (1) discharge (by bond or otherwise)
or to defend suit to enforce, any mechanics' or materialmen's lien, claim to or
right of action for such lien, which may be filed and (2) satisfy any claims or
demands arising out of, due or which may be made, directly or indirectly
attributable to the Subcontract, any work performed or supplies furnished
thereunder, or in furtherance of the construction or completion of the
subcontract work; and (c) hereby releases Contractor, any money earned by
Contractor, Contractor's sureties, the present and any future Owner, the
Property and any lender who may now or hereafter have a security interest
therein, from all claim, right of action, liability and lien which may be filed
or asserted in connection with the Subcontract.

     Dated this _____ day of _________________, 2000.

                                   As Subcontractor, General Partner of
                                   Subcontractor, or Authorized Officer of
                                   Subcontractor, above described

STATE OF _____________  )
                        ) ss.
COUNTY OF ____________  )

     Subscribed and sworn to before me this _____ day of _____________, 2000, by
__________________________, known to me to be the above-named signatory, who
personally appeared before me and acknowledged that the foregoing instrument was
freely and voluntarily executed for the uses and purposes and on behalf of the
Subcontractor therein mentioned.

     My commission expires _______________________.

                              Notary Public in and for said
                              County and State
<PAGE>

                           EXHIBIT 4 TO WORK LETTER
                           ------------------------

                              LANDLORD'S DRAWINGS
<TABLE>
<CAPTION>
CIVIL DRAWINGS
--------------
<S>       <C>       <C>
 2/11/00  1         COVER SHEET
10/11/99  2         NOTES AND LEGENDS
10/11/99  3         SITE DETAILS
10/11/99  4         SITE DETAILS
10/11/99  5         EXISTING CONDITION
10/28/99  6         SITE PLAN
10/11/99  7         SEDIMENT AND EROSION CONTROL PLAN - PHASE I
10/11/99  8         SEDIMENT AND EROSION CONTROL PLAN - PHASE II
10/11/99  9         SEDIMENT AND EROSION NOTES AND DETAILS
10/11/99  10        SEDIMENT BASIN #1 SEDIMENT & EROSION CONTROL DETAILS & NOTES
10/11/99  11        SEDIMENT BASIN #2 SEDIMENT & EROSION CONTROL DETAILS & NOTES
 11/2/99  12      SANITARY SEWER PROFILE
10/11/99  13        WATER MAIN PROFILES
 11/2/99  14      STORM DRAIN PROFILES
10/11/99  14A       STORM DRAIN PROFILES
 11/2/99  15      STORM DRAIN COMPUTATIONS
10/11/99  16        STORM DRAIN COMPUTATIONS, OVERALL
10/28/99  17        LANDSCAPE PLAN
 2/11/99  18      LANDSCAPE DETAILS, TABULATIONS AND NOTES
10/11/99  18A       TREE PRESERVATION PLAN
10/11/99  18B       TREE PRESERVATION AND NOTES
 2/11/99  19      FIRE LANE MARKING PLAN
10/11/99  20        PARKING GARAGE PLAN
10/11/99  21        SITE DISTANCE PROFILE
10/11/99  22        GEOTECHNICAL REQUIREMENTS
10/11/99  22A       GEOTECHNICAL REQUIREMENTS
10/11/99  23        STORMWATER MANAGEMENT PLAN AND NARRATIVE
 3/29/79  24      GENERALIZED DEVELOPMENT PLAN
 2/  /99  25      PROFFERS, NARRATIVE, CORRESPONDENCE WAIVERS
 6/  /99  25A     PROFFERS, NARRATIVE, CORRESPONDENCE WAIVERS
 3/29/99  26        STORMWATER MANAGEMENT PLAN (FOR INFORMATION ONLY)
 3/29/99  27        STORMWATER MANAGEMENT PLAN (FOR INFORMATION ONLY)
 3/29/99  28      STORMWATER MANAGEMENT PLAN (FOR INFORMATION ONLY)

ARCHITECTURAL DRAWINGS
----------------------

10/11/99  A-001     PROJECT DATA
10/11/99  A-002     DOOR AND PARTITION TYPES, AND DOOR DETAILS
10/11/99  A-003     FINISH SCHEDULE, DOOR AND HARDWARE SCHEDULE
11/17/99  A-201     ARCHITECTURAL SITE PLAN
  1/5/00  A-202   FIRST FLOOR PLAN
10/11/99  A-203     SECOND FLOOR PLAN
10/11/99  A-204     TYPICAL FLOOR PLAN
10/11/99  A-205     SIXTH FLOOR PLAN
10/11/99  A-206     PENTHOUSE FLOOR, MAIN ROOF, AND PENTHOUSE ROOF PLAN
11/11/99  A-207     FIRST FLOOR CORE PLAN
10/11/99  A-208     FIRST FLOOR LOBBY FINISH AND INTERIOR ELEVATIONS
11/17/99  A-209     FIRST AND SECOND FLOOR REFLECTED CEILING PLAN
10/11/99  A-210     TYPICAL FLOOR CORE, FINISH, AND REFLECTED CEILING PLAN
10/11/99  A-211     TYPICAL FLOOR REFLECTED CEILING PLAN
10/11/99  A-212     TOILET ELEVATIONS AND TYPICAL DETAILS
10/11/99  A-213     LOBBY ELEVATIONS
10/11/99  A-214     INTERIOR PLAN DETAILS
10/11/99  A-215     INTERIOR WALL SECTIONS
</TABLE>
<PAGE>

<TABLE>
<CAPTION>
<S>       <C>       <C>
10/11/99  A-216     INTERIOR SECTION DETAILS
10/11/99  A-301     ELEVATIONS
10/11/99  A-302     ELEVATIONS
10/11/99  A-401     WALL SECTIONS
10/25/99  A-402     WALL SECTIONS
10/11/99  A-403     EXTERIOR DETAILS
10/11/99  A-404     MISC. DETAILS
  1/5/00  A-405   PLAN DETAILS
10/11/99  A-406     PLAN DETAILS
10/11/99  A-501     STAIR SECTIONS AND DETAILS
10/11/99  A-502     ELEVATOR SECTION AND DETAILS
10/11/99  A-G201    FLOOR PLANS - PARKING STRUCTURE
10/25/99  A-G202    ENLARGED PLANS - PARKING STRUCTURE
10/11/99  A-G301    ELEVATIONS - PARKING STRUCTURE
10/11/99  A-G401    WALL SECTIONS - PARKING STRUCTURE
10/11/99  A-G402    WALL SECTIONS - PARKING STRUCTURE
10/11/99  A-G403    PLAN AND SECTION DETAILS - PARKING STRUCTURE
10/11/99  A-G501    PARTIAL SECTIONS AND DETAILS - PARKING STRUCTURE

STRUCTURAL DRAWINGS
-------------------

10/11/99  S-1       STRUCTURAL NOTES
  1/6/00  S-2     FIRST FLOOR FOUNDATION PLAN
10/11/99  S-3       SECOND FLOOR FRAMING PLAN
10/11/99  S-4       TYPICAL FLOOR FRAMING PLAN (3RD THRU 6TH)
10/11/99  S-5       ROOF FRAMING PLAN
10/11/99  S-6       PENTHOUSE ROOF FRAMING PLAN
10/11/99  S-7       TYPICAL DETAILS AND BEAM SCHEDULES
10/11/99  S-8       TYPICAL DETAILS
10/11/99  S-9       COLUMN SCHEDULE
10/11/99  S-10      SHEAR WALLS ELEVATIONS
10/11/99  S-11      SECTIONS
10/11/99  S-12      SECTIONS
10/11/99  GS-1      PARKING STRUCTURE P0 LEVEL FOUNDATION PLAN & STAIR ROOF FRAMING PLAN
10/11/99  GS-2      PARKING STRUCTURE P1 LEVEL FRAMING PLAN & FOUNDATION PLAN
10/11/99  GS-3      PARKING STRUCTURE P2 LEVEL FRAMING PLAN
10/11/99  GS-4      PARKING STRUCTURE STRUCTURAL NOTES
10/11/99  GS-5      PARKING STRUCTURE COLUMN SCHEDULE AND BEAM SCHEDULE
10/11/99  GS-6      PARKING STRUCTURE TYPICAL DETAILS
10/11/99  GS-7      PARKING STRUCTURE TYPICAL DETAILS
10/11/99  GS-8      PARKING STRUCTURE SECTIONS
10/11/99  GS-9      PARKING STRUCTURE SECTIONS

MECHANICAL DRAWINGS
-------------------

 3/27/00  M-1       MECHANICAL COVER SHEET
 3/27/00  M-2       MECHANICAL RISER AND FLOW DIAGRAMS
 3/27/00  M-3       MECHANICAL DETAILS
 3/27/00  M-4       MECHANICAL DETAILS
 3/27/00  M-5       MECHANICAL FIRST FLOOR CORE AND LOBBY PLAN
 3/27/00  M-6       MECHANICAL ENLARGED TYPICAL FLOOR CORE PLAN
 3/27/00  M-7       MECHANICAL 6TH FLOOR CORE PLAN
 3/27/00  M-8       MECHANICAL PENTHOUSE PLAN
 3/27/00  MP-1      MECHANICAL FIRST FLOOR PLAN
 3/27/00  MP-2      MECHANICAL SECOND FLOOR PLAN
 3/27/00  MP-3      MECHANICAL TYPICAL FLOOR PLAN (THIRD THROUGHT FIFTH)
 3/27/00  MP-4      MECHANICAL 6TH FLOOR PLAN
 3/27/00  MP-5      MECHANICAL ROOF PLAN

PLUMBING DRAWINGS
-----------------
</TABLE>
<PAGE>

<TABLE>
<CAPTION>
<S>       <C>       <C>
 3/27/00  P-1       PLUMBING COVER SHEET
 3/27/00  P-2       PLUMBING DETAILS
 3/27/00  P-3       PLUMBING FIRST FLOOR CORE, LOBBY PLAN AND PUMP ROOM
 3/27/00  P-4       PLUMBING ENLARGED TYPICAL FLOOR CORE PLAN
 3/27/00  P-5       PLUMBING DOMESTIC WATER AND SANITARY RISER DIAGRAMS
 3/27/00  P-6       PLUMBING FIRE AND STORM RISER DIAGRAMS

ELECTRICAL DRAWINGS
-------------------

 3/27/00  E-1       ELECTRICAL COVER SHEET
 3/27/00  E-2       ELECTRICAL SITE PLAN
 3/27/00  E-3       ELECTRICAL FIRST FLOOR PLAN
 3/27/00  E-4       ELECTRICAL SECOND FLOOR PLAN
 3/27/00  E-5       ELECTRICAL TYPICAL FLOOR PLAN
 3/27/00  E-6       ELECTRICAL SIXTH FLOOR PLAN
 3/27/00  E-7       ELECTRICAL PENTHOUSE PLAN
 3/27/00  E-8       ELECTRICAL FIRST FLOOR CORE AND LOBBY PLAN
 3/27/00  E-9       ELECTRICAL DETAIL SHEET
 3/27/00  E-10      ELECTRICAL TYPICAL FLOOR CORE PLAN
 3/27/00  E-11      ELECTRICAL FIRST FLOOR LOBBY PLAN
 3/27/00  E-12      ELECTRICAL POWER RISE
 3/27/00  E-13      ELECTRICAL FIRE ALARM RISER DIAGRAM AND DETAILS
 3/27/00  E-14      ELECTRICAL SCHEDULES
 3/27/00  E-15      ELECTRICAL SCHEDULES

PLUMBING DRAWINGS - PARKING STRUCTURE
-------------------------------------

 3/27/00  P-1       PLUMBING COVER SHEET
 3/27/00  P-2       PLUMBING GARAGE LEVEL - P0
 3/27/00  P-3       PLUMBING GARAGE LEVEL - P1
 3/27/00  P-4       PLUMBING GARAGE LEVEL - P2

ELECTRICAL DRAWINGS - PARKING STRUCTURE
---------------------------------------

 3/27/00  E-1       ELECTRICAL COVER SHEET
 3/27/00  E-2       ELECTRICAL GARAGE LEVEL - P0
 3/27/00  E-3       ELECTRICAL GARAGE LEVEL - P1
 3/27/00  E-4       ELECTRICAL GARAGE LEVEL - P2

ELEVATOR DRAWINGS
-----------------

 5/21/99  VT01      GENERAL ELEVATOR INFORMATION
 5/21/99  VT02        HOISTWAY, PIT MACH. RM. PLAN AND HOISTWAY SECTION ELEV. 1-4
 5/21/99  VT03      HOISTWAY SECTIONS ELEVATORS 1-4
 5/21/99  VT04        HOISTWAY, PIT MACH. RM. PLAN AND HOISTWAY SECTION ELEVATOR 5

ADDITIONAL SHOP DRAWINGS
------------------------

4/11/00             1ST FLOOR SHEET METAL LOOP AND PERIMETER DUCT
4/11/00             2ND FLOOR SHEET METAL LOOP AND PERIMETER DUCT
4/11/00             3RD THRU 6TH FLOOR SHEET METAL LOOP AND PERIMETER DUCT
4/11/00             6TH FLOOR SHEET METAL LOOP AND PERIMETER DUCT
4/11/00             PENTHOUSE -  SHEET METAL
4/11/00             RISER DRAWINGS - SHEET METAL
</TABLE>
<PAGE>

                           EXHIBIT 5 TO WORK LETTER
                           ------------------------

BUILDING IMPROVEMENTS

The Landlord will provide the following Building Improvements as shown on
Landlord's Drawings and as summarized as follows:

A.   Typical Floors Areas:

          1.   Elevator Lobby: Typical floor elevator lobbies shall be complete
               and operational including the following: primed elevator doors
               and frames ready to receive Tenant finish, thresholds, call
               buttons, directional lanterns, code required signage, code
               required life safety devices, fire rated drywall enclosure at
               elevator shaft openings.

               To the extent directed in Tenant's Space Plan, Landlord shall
               delete the following items and share with Tenant credits
               resulting from deletion:  Delete elevator lobby ceiling and
               lighting, Delete drywall furring at all concrete shear walls.

          2.   Men's and Women's Restrooms: Finished and operational, with
               ceramic tile wet walls and ceramic tile floor.  Dual hi-low
               drinking fountains located adjacent to restroom entrances on each
               floor.

          3.   Adjustable horizontal mini-blinds installed on all exterior
               windows throughout the Premises (Levelor Reviera Sheerview Blinds
               with 15.7 slats per foot, .008 gauge slats, color to be selected
               by Landlord and acceptable to Tenant).  Landlord agrees to
               substitute mini-blinds with "Mecho" Shades (Mecho Shade Slimeline
               Bracket for Reverse Roll Shade); any cost increase to provide
               Mecho Shades shall be a Tenant cost.

          4.   All building columns furred, drywalled, taped and bedded and
               ready to receive paint or other finish.

               To the extent directed in Tenant's Space Plan, Landlord shall
               delete the following items and share with Tenant credits
               resulting from deletion:  Delete drywall column enclosure on all
               interior columns (two per floor).

          5.   Any wall surface beneath exterior windows to be insulated,
               furred, drywalled, left untapped and unpainted for future removal
               by Tenant's contractor to allow for future installation of
               telecommunication, data, and electrical devices.

          6.   Core partitions finished on Tenant side ready to receive paint or
               other finish.

          7.   Two (2) exit stairwell finished in accordance with Landlord's
               Drawings. Tenant, at Tenant's option and cost can upgrade
               finishes and lighting in stairwells with Landlord's approval.
               All said finishes shall be in compliance with all applicable
               building and fire codes.  Restoration to Base Building condition
               at end of Lease may be a requirement of approval.

          8.   Two (2) electrical rooms, two (2) mechanical rooms provided per
               floor, and one (1) telephone room provided per floor in
               accordance with Landlord's drawings.

          9.   All concrete flooring level, complete and ready to accept Carpet,
               VCT or other floor applications in accordance with Plans and
               standard industry tolerances (not including topping or slab prep
               for such materials) not to exceed a flatness to standard of  1/4
               inch in ten feet non-cumulative.
<PAGE>

          10.  Ceiling Height: The typical slab-to-slab eight is 12'-4" with the
               typical flat slab of 12" depth with (exterior only) column
               capitals and 14" slab on end bay conditions, allowing for a
               finished ceiling height of 9'-0" in the Demised Premises.

          11.  Floor Load: All Tenant spaces shall have a floor load of 100 lbs.
               Per square foot live (including partition loads). High density
               storage loads of 250 lbs. Per square foot is allowed for between
               column grids 3.6 and 5, B and C (per Landlord's Drawings).

          12.  Wet Columns: Two wet columns per floor will be provided for use
               by tenants for plumbing tie-ins.  Waste, vent, and supply taps
               with shut-off valves are provided above ceiling height.

B.   BUILDING SECURITY:

          1.   All building entries and building elevators shall be tied into a
               Kastle Building Card Key System.  After hours access will be by
               Card Key only.  At Tenant's option, during normal business hours,
               access to Tenant's floors could be limited to Card Key access for
               floors other than its main reception and mailroom / /delivery
               floors.

          2.   Keys and security cards will be provided at a ratio of four per
               1,000 usable square feet leased, free of charge.  In the event
               Tenant requires additional keys or security cards, Landlord shall
               provide same at Landlord's actual cost.

          3.   After-hours access reports can be provided to Tenant on a daily
               basis as part of a coordinated Security Plan.

          4.   Building Security and Fire / Life Safety Systems will be tied
               into an automatic Central Station Monitoring and Dispatch System.

          5.   Card key access to Executive Level PO.

C.   BUILDING ACCESSIBILITY:

          1.   24-Hours per day - 365 days per year, with at least one (1)
               passenger elevator available at all times, except in emergencies.

D.   ELEVATOR AND LOADING FACILITIES:

          1.   Three (3) geared traction elevators in each tower.  Each elevator
               has a capacity of 3,500 lbs., travels at 350 f.p.m. and services
               all levels including the main lobby and office levels.  A fourth
               "Swing Cab" is also provided for (dual purpose) both passenger
               and service car loading.  Capacity is 4,000 lbs. At 350 f.p.m.
               with rear door access at the lobby level for deliveries.  A 2,500
               lb., 150 f.p.m. hydraulic elevator serves all three levels of the
               parking structure.

          2.   The loading area is located adjacent to the buildings East
               Elevation through an 8'-0" x  6'-0" double door.

E.   ELECTRICAL SYSTEM:

          1.   The building power distribution system will be served from a pad
               mounted Virginia Power Transformer.  The building power will be
               distributed from a 4,000 AMP, 277 / 408 Volt, Three Phase, 4W
               distribution switchboard, through two (2) vertical bus-duct
               risers serving all tenant floors.  The West bus-duct will be
               rated for 2,000 AMP, 277 / 408 Volt, three phase, 4W and the East
               bus-duct is rated for 1,600 AMP, 277 / 408 Volt, three phase, 4W.
               Power is distributed to the tenant floor from bus-duct plug-in
               units.
<PAGE>

          2.   Panelboards in each of the two (2) typical floor electrical rooms
               will be as follows:

               a.   One (1) 400 AMP, 277 / 408 Volt, three phase, 4W, 39-pole
                    panel for tenant area lighting, heating and air
                    conditioning.

               b.   One (1) 400 AMP, 120 / 208 Volt, three phase, 4W, 84-pole
                    panel for tenant area receptacles.

               c.   One (1) 112.5 KVA K-13 rated transformer.

          3.   All bussing in panel boards, bus-duct, and switchboard will be
               aluminum.  All branch feeders and circuiting shall be copper.

          4.   The building load densities will be as follows:

               a.    Building Total:        19 Watts / Usable Square Feet
               b.    Lighting (Tenant):     02 Watts / Usable Square Feet
               c.    Receptacles (Tenant):  06 Watts / Usable Square Feet
               d.    HVAC:                  07 Watts / Usable Square Feet
               e.    Miscellaneous:         01 Watts / Usable Square Feet
               f.    Spare (Tenant):        03 Watts / Usable Square Feet
               Note: Spare capacity is provided at panel board.

          5.   Tenant will be able to obtain spare capacity from extension of
               the vertical bus-duct in a spare bus-tap opening.

F.   MECHANICAL SYSTEM:

          1.   Perimeter and interior zones will be air conditioned by packaged,
               water-cooled self-contained variable air volume (VAV) air
               conditioning units with integral water coil economizer (two units
               per floor) conveying air through medium pressure loop ductwork to
               VAV terminals.

          2.   Perimeter and interior zones on each floor will be served by
               cooling only, pinchoff type VAV boxes (stocked on floors as
               Building Improvements at Landlord's cost) and installed under
               Tenant Improvement Work (Tenant's cost) as indicated on Base
               Building Mechanical Floor Plans MP-3 and MP-4 drawings, dated
               3/27/00.

          3.   Building heating will be accomplished by a "skin system"
               consisting of series-flow fan powered VAV terminals (8 per
               typical floor) with electric resistance heating coils as
               indicated on Base Building Mechanical Floor Plans MP-3 and MP-4
               drawings, dated 3/27/00.  The perimeter fan power VAV terminals
               will also serve a portion of the skin cooling load and will be
               provided and installed under core and shell work as indicated on
               Base Building Mechanical Floor Plans MP-3 and MP-4 drawings,
               dated 3/27/00.

          4.   The entire HVAC system will be installed as part of the core and
               shell work as indicated on Base Building Mechanical Floor Plans
               MP-3 and MP-4 drawings, dated 3/27/00, with the exception of the
               cooling only VAV terminals and cooling only discharge ductwork
               and supply and return outlets.  Cooling only VAV boxes to be
               provided by Landlord, at Landlord's sole cost, have been designed
               at an approximate ratio of 1 box per 750 square feet and one box
               per 1,500 square feet for the perimeter and interior zones
               respectively.

          5.   Heating and cooling design parameters:

               a.   Indoor Conditions:
                    Summer:  75 degrees F db / 50% RH
                    Winter:  72 Degrees F db / no humidity control
<PAGE>

               b.   Outdoor Conditions:
                    Summer:  95 degrees F db / 78 degrees F wb
                    Winter:  0 degrees F db

               c.   Lighting Heat Resistance:  2.0 Watts per square foot

               d.   Equipment Heat Release:  3.0 Watts per square foot

          6.   Outdoor air will be provided at a rate of 20 CFM per person (as
               per the latest edition of the International Mechanical Code).
               The number of people will be based on normal office occupancy of
               seven (7) people per 1,000 square feet.  In addition, 5% of the
               occupied office space has been calculated as conference rooms (at
               50 people per 1,000 square feet).  A constant supply of outdoor
               air will be introduced on each floor.

          7.   The condenser water system is available for 7 x 24 operation.
               Approximately 10 tons of supplemental capacity has been provided
               per floors.  After-hours billing rate, included in Lease, shall
               be applied for  condenser water used after normal building hours
               of operation.

G.   BUILDING MANAGEMENT SYSTEM:

          1.   A building management system will be provided to monitor and
               control mechanical equipment.  The system will be a PC-based,
               stand-alone type system.  The system will be capable of
               monitoring and controlling all specified functions from a remote
               location via modem.

          2.   Normal building hours will be 8 a.m. to 7 p.m. Monday through
               Friday and 9 a.m. to 2 p.m. on Saturday.  After hours system
               activation will be by the Tenant through building management
               system.  After hours billing rates will be in effect.

H.   COMMUNICATIONS:

          1.   The building main telecom room will be located on the first floor
               of the building.  Four (4) four (4) inch diameter conduits will
               extend from the main Telecom Room to the property line for
               telephone company connections.  Four (4) four (4) inch conduits
               will extend from the main Telecom Room up to each typical floor
               Telecom Room for tenant cabling.

          2.   Fiber optics is available from Bell Atlantic and other dial tone
               providers.

          3.   Three (3) four (4) inch diameter conduits are provided to each
               building from Fox Mill Road to the main Telecom Room on the 1st
               floor for future fiber optics service.

J.   LIFE SAFETY:

          1.   The building will have automatic fire sprinklers throughout.
               Fire standpipes and fire alarm system will be provided pursuant
               to the applicable building codes.  Sprinkler piping will be
               installed with upturned heads at a maximum ratio of one head per
               225 square feet but with piping designed to accommodate one head
               per 130 square feet under Tenant Improvement Work.

          2.   A closed-circuit, electrically supervised, non-coded addressable
               fire alarm system will be provided, consisting of a main control
               panel, manual fire alarm pull stations, sprinkler water flow
               alarm devices, smoke detection devices, flashing signals, horns,
               supervisory control and remote-indicating annunciators and all
               other items of equipment required for a complete fire alarm
               system to comply with local codes including any required fire
               hose valve cabinets and fire extinguishers, for open plan per
               Building
<PAGE>

               Improvements. Additional requirements necessitated by Tenant
               development shall be provided by Tenant.

          3.   Emergency electrical service will be provided by a pad-mounted
               diesel generator which will produce 175 KW at 277 / 408 Volts,
               three phase, 4W.  The generator will provide emergency power to
               all designated emergency light fixtures and exit signs, fire
               alarm system, security system, fire pump, and elevator.

          4.   Empty conduits have been provided for a Tenant supplied generator
               which would be placed adjacent to the Landlord's emergency
               generator.
<PAGE>

EXHIBIT 6 TO WORK LETTER
------------------------

SCHEDULE OF DATES

        Event                                               Date
        -----                                               ----

        Space Plan Deadline for both Phases                 May 8, 2000*

        Phase I Draft Architectural Drawings Deadline       June 5, 2000

        Phase II Draft Architectural Drawings Deadline      July 24, 2000

        Phase I Early Delivery Date                         June 19, 2000

        Phase I Delivery Date                               July 1, 2000

        Phase II Delivery Date                              August 21, 2000

        Anticipated Commencement Date                       September 18, 2000

        Anticipated Phase II Completion Date                January 1, 2001

        *The deadline was met in a timely manner.
<PAGE>

EXHIBIT 7 TO WORK LETTER
------------------------

CEILING DESIGN STANDARDS

Landlord approves of the Reflected Ceiling Plan dated April 20, 2000, prepared
by Studio Architects on the following conditions:

1.   All four floors are designed consistently and substantially in accordance
with the Studio Plan dated April 20, 2000, as further modified below.

2.   At the perimeter, there shall be installed a band of ceiling at the 9'-0"
A.F.F. height, from column to column, from the window head to the back/interior
side of the perimeter columns.  This shall be consistent with the intent of the
Building Improvements and shall be either painted drywall or building standard
lay-in ceiling grid and tiles, at your option.  This work is part of Tenant
Work, at Tenant's cost.

3.   The perimeter, fan-powered VAV boxes shall be installed per the Building
Improvements design intent, including the installation of the air bars within
the perimeter ceiling noted in 2 above.  This work is part of  Landlord's
Building Improvements.

4.   The perimeter, cooling-only VAV boxes (provided at Landlord's cost) shall
be installed (at Tenant's cost) per the Building Improvements design intent and
criteria, unless Tenant's design loads are higher.  However, if the main loop
duct is shifted as proposed on the above referenced plan, these cooling-only VAV
zones should be resized to handle all of the cooling load "outboard" of the main
loop duct, using our Building Improvements design criteria.  This work,
including main loop duct shift shall be part of Tenant Work at Tenant's cost.
The main loop duct shifts shall be done as part of Landlord's Building
Improvements, however, any costs/impacts in relocating same shall be at Tenant's
cost.

5.   The interior cooling-only VAV boxes (provided at Landlord's cost) shall be
installed (at Tenant's cost) per Building Improvements design criteria and
intent, unless Tenant's design loads are higher.  Again, if the main loop duct
is shifted, these cooling-only VAV zones shall be resized to handle all of the
cooling load "inboard" of the main loop duct, using our Building Improvements
design criteria.  This work, shall be part of the Tenant Work at Tenant's cost.
The main loop duct shifts shall be done as part of the Landlord's Building
Improvements, however, any costs/impacts in relocating same shall be at Tenant's
cost.

6.   The main ducts may be relocated from the two HVAC mechanical rooms as shown
on the above referenced drawing, only to the extent that this shift does not
impact the equipment within the mechanical rooms, and the efficiency of the duct
work.  This work shall be done as part of the Landlord's Building Improvements,
however, any costs/impacts in relocating this duct shall be at Tenant's cost.

7.   All costs to revise the sprinkler system to accommodate this design shall
be Tenant's cost.  We anticipate that some, if not all of the work shall be done
under Landlord's Building Improvements contract, subject to reimbursement by
Tenant.

8.   Non-standard round fluorescent pendant lights may be used, if installed per
the grid pattern shown on the above referenced drawings.  These fixtures are
part of the Tenant's Work and are at Tenant's cost.

9.   Coordination with Landlord's Building Improvements is critical.  Any
impacts/delays in Landlord obtaining inspections, approvals or Certificates of
Occupancy due to the modifications to its work caused by Tenant's design shall
be Tenant Delay.  Landlord will work with Tenant to minimize potential impacts
and will advise Tenant as soon as possible of potential delays during the course
of construction.
<PAGE>

                                 OFFICE LEASE

                                    between

                             DTC ASSOCIATES, LLC,
                     a Virginia limited liability company
                                 (as Landlord)

                                      and

                            LIFEMINDERS.COM, INC.,
                            a Delaware corporation
                                  (as Tenant)

Section                                                      Page
-------                                                      ----

1.     PRINCIPAL TERMS                                          1

2.     GENERAL COVENANTS                                        3

3.     TERM                                                     3

4.     RENT                                                     3

5.     COMPLETION OR REMODELING OF THE PREMISES                 3

6.     OPERATING EXPENSES                                       4

7.     SERVICES                                                 4

8.     QUIET ENJOYMENT                                          6

9.     DEPOSIT                                                  6

10.    CHARACTER OF OCCUPANCY                                   6

11.    MAINTENANCE, ALTERATIONS AND REENTRY BY LANDLORD         7

12.    ALTERATIONS AND REPAIRS BY TENANT                        8

13.    CONSTRUCTION LIENS                                       9

14.    SUBLETTING AND ASSIGNMENT                                9

15.    DAMAGE TO PROPERTY                                      11

16.    INDEMNITY                                               11

17.    SURRENDER AND NOTICE                                    11

18.    INSURANCE, CASUALTY, AND RESTORATION OF PREMISES        11

19.    CONDEMNATION                                            12

20.    DEFAULT BY TENANT                                       12

21.    DEFAULT BY LANDLORD                                     14

22.    SUBORDINATION AND ATTORNMENT                            15

23.    REMOVAL OF TENANT'S PROPERTY                            15
<PAGE>

24.    HOLDING OVER: TENANCY MONTH-TO-MONTH                    16

25.    PAYMENTS AFTER TERMINATION                              16

26.    STATEMENT OF PERFORMANCE                                16

27.    MISCELLANEOUS                                           16

28.    AUTHORITIES FOR ACTION AND NOTICE                       18

29.    PARKING                                                 18

30.    SUBSTITUTE PREMISES                                     18

31.    BROKERAGE                                               18

32.    COUNTERPARTS                                            19

33.    ADDENDUM/EXHIBITS                                       19
<PAGE>

                                INDEX OF TERMS

                                                                 Page
                                                                 ----
Adequate Assurance                                                10
Affiliate of Tenant's Parent                                      11
Affiliate of Tenant                                               11
Allowance                                                        J-5
Alterations                                                        8
Ancillary Uses                                                     6
Anticipated Commencement Date                                    J-5
Anticipated Phase II Completion Date                             J-5
Applicable Laws                                                 J-10
Applicable Laws                                                    6
Approved Space Plans                                             J-2
Arbitrator                                                     Add-2
Assumed Lease                                                  Add-2
Attachments                                                        2
Authorized Signatory                                             G-1
Backup System                                                  Add-2
Bankruptcy Proceeding                                             13
Base Operating Expenses                                          C-1
Base Rent                                                          1
Battery Source                                                 Add-2
Brokers                                                           18
Building                                                           1
Building Complex                                                   3
Building Manager                                                  18
Building Systems                                                  15
Ceiling Reimbursement                                          Add-6
Chillers                                                       Add-3
Collocation Services                                              11
Common Areas                                                       3
Communications Equipment                                       Add-3
Comparable Building                                            Add-2
Construction Lender                                             J-16
Contract                                                         J-3
Contractor                                                      J-16
Control                                                           11
Controls                                                          11
Cooperating Broker                                                 2
Cost Savings Improvements                                        C-2
Declaration                                                        6
Delivery Date                                                    J-4
Deposit                                                            2
Dishes                                                         Add-3
Dulles Executive Plaza Complex                                    13
Environmental Law                                                  6
Estimated Payment                                                C-4
Event of Default                                                  12
Excess Costs                                                     J-5
Expiration Date                                                    3
Final Working Drawings                                           J-3
Force Majeure                                                    J-6
Generator                                                      Add-2
Guarantor                                                          2
Hazardous Materials                                                6
Initial Tenant Finish                                              3
Initial Term                                                       1
Invitees                                                           4
Landlord                                                           1
Landlord Delay                                                   J-6

                                       i
<PAGE>

Landlord's Accountants                                           C-1
Landlord's Architect                                             J-1
Landlord's Broker                                                  2
Landlord's Contractors                                           J-3
Landlord's Drawings                                              J-1
Landlord's Notice Address                                          2
Landlord's Notice                                              Add-1
Landlord's Scope of Review                                       J-2
Landlord's Tax I.D.                                                2
LC Maximum                                                     Add-5
LC Termination Date                                            Add-5
Lease                                                            J-1
Lease                                                            D-1
Lease                                                            G-1
Lease Year                                                         3
Legal Holidays                                                     4
Letter of Credit                                               Add-5
Mortgage                                                          15
Mortgagee                                                         14
Net Landlord Delay                                               J-6
Operating Expense Year                                           C-1
Operating Expenses                                               C-1
Option                                                         Add-1
Option Term                                                    Add-1
Ordinary Business Hours                                            4
Outside Date                                                       4
Parent of Tenant                                                  11
Parking                                                            2
Permitted Transfer                                                10
Permitted Transferee                                              10
Permitted Use                                                      2
Phase I                                                          J-1
Phase II                                                         J-1
Premises                                                           1
Primary Use                                                        6
Prime Rate                                                        14
Project                                                         J-16
Property                                                        J-16
Real Property                                                      3
Reasonable Rental Value                                           14
Related Equipment                                              Add-2
Related Equipment                                              Add-3
Reletting Expenses                                                13
Rent Payment Address                                               2
Rent(s)                                                            3
Rentable Area                                                    C-1
Repair Period                                                     12
Required Capital Improvements                                    C-2
Requirements                                                     J-3
Roof                                                           Add-3
Roof Space                                                     Add-3
Security                                                           4
Services                                                           4
Space Plans                                                      J-1
Subcontractor                                                   J-18
Super Fund                                                         6
Super Lien                                                         6
Taxes                                                            C-1
Tenant                                                             1
Tenant Delay                                                     J-6
Tenant Work                                                      J-4
Tenant's Accountants                                             C-4
Tenant's Agents                                                   11

                                      ii
<PAGE>

Tenant's Architect                                               J-1
Tenant's Contractors                                             J-3
Tenant's Dispute Notice                                        Add-1
Tenant's Notice Address                                            2
Tenant's Notice                                                Add-1
Tenant's Notice                                                   10
Tenant's Pro Rata Share                                          C-1
Tenant's System                                                    4
Tenant's Tax I.D.                                                  2
Term                                                               3
Transfer                                                           9
Transferee                                                         9
Work                                                            J-16
Work Letter                                                        3
Working Drawings                                                 J-8

November 9, 2000
                                      iii

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