<PAGE>

                                                                    Exhibit 10.2

                                 1899 WYNKOOP
                             OFFICE BUILDING LEASE
                                    BETWEEN
                          CENTENNIAL VENTURE I, LLC,
                                 LANDLORD, AND
                       WEBB INTERACTIVE SERVICES, INC.,
                                    TENANT

                               TABLE OF CONTENTS
                               -----------------

<TABLE>
<S>                                                                          <C>
1.       Premises.........................................................    1

2.       Term and Possession..............................................    1

3.       Rent.............................................................    3

4.       Security Deposit.................................................    4

5.       Rent Adjustment..................................................    4

6.       Character of Occupancy...........................................    8

7.       Services and Utilities...........................................    9

8.       Quiet Enjoyment..................................................   11

9.       Maintenance and Repairs; Building Management.....................   11

10.      Alterations and Additions........................................   12

11.      Entry by Landlord................................................   13

12.      Mechanic's Liens.................................................   13

13.      Damage to Property; Injury to Persons............................   14

14.      Insurance........................................................   14

15.      Damage or Destruction to Building................................   16

16.      Condemnation.....................................................   17

17.      Assignment and Subletting........................................   18

18.      Estoppel Certificate.............................................   19

20.      Landlord's Lien..................................................   23

21.      Uniform Commercial Code..........................................   23

22.      Removal of Tenant's Property.....................................   23
</TABLE>

                                      -i-
<PAGE>

<TABLE>
<S>                                                                          <C>
23.      Holdover.........................................................   23

24.      Common Areas.....................................................   23

25.      Surrender and Notice.............................................   24

26.      Sales; Conveyance and Assignment.................................   24

27.      Subordination; Non-Disturbance and Attornment....................   24

28.      Payments After Termination.......................................   24

29.      Authorities for Action and Notice................................   25

30.      Liability of Landlord............................................   25

31.      Brokerage........................................................   25

32.      Tenant's Taxes...................................................   26

33.      Substitution of Premises.........................................   26

34.      Rights Reserved to Landlord......................................   26

35.      Force Majeure Clause.............................................   27

36.      Signage..........................................................   27

37.      Attorneys' Fees..................................................   27

38.      Miscellaneous....................................................   27

39.      Hazardous Materials..............................................   30

40.      Parking..........................................................   31

41.      Right to Renew...................................................   31

42.      Letter of Credit.................................................   32
</TABLE>


EXHIBIT A      DESCRIPTION OF PREMISES
EXHIBIT B      LEGAL DESCRIPTION
EXHIBIT C      COMMENCEMENT DATE AGREEMENT
EXHIBIT D      WORK LETTER
EXHIBIT E      RULES AND REGULATIONS

                                     -ii-
<PAGE>

                       SUMMARY OF BASIC LEASE PROVISIONS

LANDLORD:      Centennial Venture I, LLC

ADDRESS OF     120 17th Street, 8th Floor
LANDLORD:      Denver, Colorado  80202
               (303) 436-9191

TENANT:        Webb Interactive Services, Inc.

ADDRESS OF                                        1899 Wynkoop Street, Suite 600
TENANT:        Premises Address                   Denver, Colorado  80202
               Business Home Office
               Address                            1800 Glenarm, Suite 600
                                                  Denver, Colorado 80202
               Business Home Office
               Telephone No.                      303-296-9200


PREMISES:           Suite 600, containing approximately 21,398 rentable square
                    feet of space, as shown crosshatched on Exhibit A.

TENANT'S PRO-RATA        12.972%
SHARE:

LEASE TERM:         Five (5) Years Two (2) Months

BASE RENT:                                        Monthly        Annual
                         Period                   Base Rent      Base Rent
                         ------                   ---------      ---------
                         Months 1-2               $46,362.33     See Paragraph 3
                         Months 3-36              $46,362.33     $556,348.00
                         Months 37-62             $49,928.67     $599,144.00

EXPENSE STOP:            $6.50
SECURITY DEPOSIT:        See infra Paragraph 4
PREPAID RENT:            $46,362.33

                                     -iii-
<PAGE>

                                 1899 WYNKOOP

                             OFFICE BUILDING LEASE

     THIS LEASE is made this 8th day of December 1999, by and between Centennial
                                                                      ----------
Venture I, LLC., a Colorado Limited Liability Company ("Landlord") and Webb
----------------
Interactive Services, Inc., a Colorado corporation ("Tenant").

     1.   Premises: Landlord hereby leases to Tenant those certain premises
          --------
described in Exhibit A, attached hereto and incorporated herein by this
reference, and the drawings referred to therein, consisting of a total of
approximately 21,398 rentable square feet of space on the 6th floor, suite 600
(the "Premises"), in the Building (hereinafter defined) to be erected on the
real property more particularly described on Exhibit B attached hereto and
incorporated herein by this reference, together with a non-exclusive right,
subject to the provisions hereof, to use all appurtenances thereunto, including,
but not limited to, any areas designated by Landlord for use by tenants of the
Building (the Building, the parking garage, the real property on which the same
is situated, other areas and appurtenances are hereinafter collectively
sometimes called the "Building Complex"). The Building is commonly known as 1899
Wynkoop and is located at 1899 Wynkoop Street, Denver, Colorado 80202 (The
"Building"). This Lease is subject to the terms, covenants and conditions set
forth herein and Tenant and Landlord each covenant as a material part of the
consideration for this Lease to keep and perform each and all of said terms,
covenants and conditions to be kept and performed by them.

     2.   Term and Possession:
          -------------------

          (a)  The Term of this Lease shall be approximately five (5) years and
     two (2) months to commence on the Commencement Date and to end, unless
     sooner terminated, at midnight on the last day of the sixty-second (62nd)
     full calendar month thereafter. Promptly after the Commencement Date,
     Landlord and Tenant will execute an agreement in recordable form
     (hereinafter referred to as the Commencement Date Agreement, a form of
     which is attached hereto as Exhibit C) stating, among other things, the
     rentable square foot area of the Premises, the commencement and expiration
     dates of this Lease and the Base Rent.

          (b)  "Commencement Date" shall mean the earlier of the following
     dates:

               (1)  The date upon which the Tenant takes possession or commences
          the operation of its business in the Premises; or

               (2)  The date upon which the Premises are Ready for Occupancy
          (hereinafter defined);

     provided, that under either subparagraph 2(b)(1) or (2) the actual
Commencement Date shall not be prior to the Scheduled Commencement Date.

          (c)  The Scheduled Commencement Date shall be May 1, 2000. Tenant's
     actual Commencement Date shall be established by the Commencement Date
     Agreement. Prior to the Commencement Date, Landlord shall cause the
     Premises to be prepared for occupancy, as provided in the Work Letter
     attached to this Lease as Exhibit D. The cost of completion of the tenant
     improvement work to the Premises shall be borne by the parties as provided
     in the Work Letter. Other than as set forth in the Work Letter Landlord
     shall have no obligation for the completion of the Premises, and Tenant
     shall accept the Premises in its "as is" condition on the Commencement
     Date. "Ready for Occupancy" as that term is used herein shall mean the date
     when all major construction aspects of the Building and the Premises to be
     performed by Landlord and Tenant to the extent agreed to in the Work Letter
     are substantially completed although punch list items are not completed.
     The certificate of the architect in charge of supervising the completion of
     the Premises shall control the date upon which the Premises are Ready for
     Occupancy. Landlord shall not have any obligation for the repair or
     replacement of any portions of the interior of the Premises, including but
     not limited to carpeting, draperies, window coverings, wall coverings or
     painting, which are damaged or wear out during the term hereof, regardless
     of the cause therefor, except as may otherwise be specifically set
<PAGE>

     forth in this Lease. Except as expressly provided in the Work Letter, any
     tenant improvements to the Premises for which Landlord shall be responsible
     shall be subject to the following:

               (1)  Tenant may substitute different new material
          (except exterior window coverings) or make changes to the final
          working drawings and specifications only with Landlord's prior express
          approval, which may be withheld in Landlord's sole discretion. Any
          substitutions or changes must be shown on the working drawings and in
          the specifications and shall be of equal or better quality than the
          items originally designated and must be deemed by Landlord to be in
          conformance with the quality and design criteria established within
          the Building. In the event Landlord approves the requested
          substitution or change, Tenant shall bear the cost of making any
          changes to the working drawings and specifications as well as any
          additional costs occasioned by the change or substitution, including
          costs of disruption and delay. Tenant shall pay such additional costs
          to Landlord within ten (10) days of receipt of Landlord's invoice for
          the same.

               (2)  If Landlord shall be delayed in sufficiently completing said
          work as a result of Tenant's request for substitution of materials,
          finishes, fixtures, equipment or installations or any other change to
          the working drawings and specifications requested by Tenant and
          approved by Landlord, or the failure of Tenant to provide timely
          approvals of working drawings or other specifications necessary for
          completion of the work, then the Commencement Date of the Term of this
          Lease and the payment of Base Rent shall not be extended, but shall be
          accelerated as provided in the Work Letter.

               (3)  If Tenant occupies or begins to conduct business in all or
          any portion of the Premises before the Premises are Ready for
          Occupancy, such occupancy and conducting of its business by Tenant
          shall be subject to all provisions of this Lease which reasonably and
          logically apply thereto; provided, however, that Tenant shall not be
          required to pay any Base Rent for the Premises for any period it
          occupies and conducts business in the Premises prior to the Scheduled
          Commencement Date. Such prior occupancy shall not operate to commence
          the Term of the Lease for all or any part of the Premises.

               (4)  If Landlord is delayed in delivering possession of all or
          any portion of the Premises to Tenant on or before the Scheduled
          Commencement Date for reasons not attributable to Tenant's conduct or
          requests, including, but not limited to, delays caused by governmental
          authorities, then Tenant shall take possession of the Premises on the
          date (not later than four (4) months after the Scheduled Commencement
          Date) when Landlord delivers possession of all of the Premises and
          Tenant obligation to pay Base Rent and the Termination Date shall be
          extended for an equivalent period of time. Except as provided in
          subparagraph 2(c)(6), this Lease shall not be void or voidable nor
          shall Landlord be liable to Tenant for any loss or damage resulting
          from any delay in delivering possession of the Premises to Tenant, its
          servants, agents or independent contractors, no Base Rent shall be
          payable by Tenant for the period prior to the date on which Landlord
          can so deliver possession of all of the Premises.

               (5)  Taking possession of all or any portion of the Premises by
          Tenant shall constitute Tenant's acceptance of the Premises or such
          portion thereof as being in satisfactory condition, subject only to
          punch list items listed in writing in a notice delivered by Tenant to
          Landlord as provided for in the Work Letter.

               (6)  If the Premises are not Ready for Occupancy by the dates
          indicated below for reasons other than delays caused by Tenant
          (including those set forth in Exhibit D), delays caused by
          governmental authorities or Force Majure events the Landlord shall pay
          Tenant the amounts set forth below for each day of delay:

                    (A)  If the Premises are not Ready for Occupancy on or
               before April 15, 2000, Landlord shall pay Tenant its actual
               Holdover Rent (hereinafter defined) not to

                                      -2-
<PAGE>

               exceed $500.00 per each day of delay thereafter, until the
               Premises are Ready for Occupancy, through April 30, 2000. As used
               herein, Holdover Rent shall mean the difference between Tenant's
               current base rent for its premises located at 1800 Glenarm, Suite
               600, Denver, Colorado 80202, Denver, Colorado ($19.00 per square
               foot per year), and the rate it is charged by its landlord for
               said premises from and after April 15, 2000.

               Tenant agrees that it shall use its best efforts to negotiate the
               most favorable holdover rate with its current landlord; and

                    (B)  If the Premises are not Ready for Occupancy on or
               before April 30, 2000, Landlord shall pay Tenant its actual
               Holdover Rent not to exceed $750.00 per each day of delay
               thereafter, until the Premises are Ready for Occupancy through
               June 30, 2000; provided that, if Landlord does not permit Tenant
               to occupy one or more entire floors of said premises, Landlord
               shall pay Tenant $750 per day from and after April 30, 2000.

                    (C)  Notwithstanding the foregoing, if, on or after April 1,
               2000, Tenant is required to vacate one or more full floors
               included at its premises at 1800 Glenarm, then from and after the
               date Tenant is required to vacate, the amount Landlord is
               required to pay Tenant shall be $500.00 per day pursuant to
               subparagraph (6)(A) and $750.00 per day pursuant to subparagraph
               (6)(B). The amount set forth in this subparagraph (6)(C) shall be
               in place of the amounts set forth in subparagraphs (6)(A) and (B)
               and not in addition thereto.

               (7)  If the Landlord has not commenced construction of the
          Leasehold Improvements by February 15, 2000, for reasons other than
          delays caused by Tenant, delays caused by governmental entities or
          Force Majure events, Tenant may terminate this Lease without liability
          by giving Landlord written notice of the termination on or before
          February 18, 2000. If construction of the Leasehold Improvements is
          commenced by February 15, 2000, or if Tenant fails to exercise the
          termination right in accordance with this subparagraph this
          termination right shall lapse and be null and void.

               (8)  If the Premises are not Ready for Occupancy by July 1, 2000,
          for reasons other than delays caused by Tenant, delays caused by
          governmental entities or Force Majure events, Tenant may terminate
          this Lease without liability by giving Landlord written notice of the
          termination on or before July 5, 2000. If the Premises are Ready for
          Occupancy by July 1, 2000, or if Tenant fails to exercise the
          termination right in accordance with this subparagraph this
          termination right shall lapse and be null and void

               (9)  If the Premises are not Ready for Occupancy by July 31,
          2000, for reasons other than delays caused by Tenant, Tenant may
          terminate this Lease without liability by giving Landlord written
          notice of the termination on or before August 3, 2000. If the Premises
          are Ready for Occupancy by July 31, 2000, or if Tenant fails to
          exercise the termination right in accordance with this subparagraph
          this termination right shall lapse and be null and void.

     3.   Rent:  Tenant shall pay to Landlord, rent for the Premises ("Base
          ----
Rent") in accordance with the following schedule:

                               MONTHLY            ANNUAL
PERIOD                         BASE RENT          BASE RENT
Months 1-2                     $46,362.33         See Paragraph 3
Months 3-36                    $46,362.33         $556,348.00
Months 37-62                   $49,928.67         $599,144.00

                                      -3-
<PAGE>

     All installments of Base Rent shall be payable in advance, on the first
(1st) day of each calendar month during the term hereof. Base Rent for any
partial month during the term hereof shall be prorated based upon the number of
days during each of said months that the Lease term was in effect. The full
first month's Base Rent shall be due and payable on the date of execution of
this Lease by Tenant. All Base Rent shall be paid without notice, demand,
deduction or offset, at the office of Landlord or to such other person or at
such other place as Landlord may designate in writing. Notwithstanding anything
to the contrary set forth herein, Tenant may occupy the Premises and payment of
Base Rent and Tenant's Pro Rata Share of Operating Expenses shall be abated for
a period commencing on the Commencement Date and terminating on the last day of
the second month of the Lease Term (the "Abatement Rent Period"). If at any time
during the Primary Term, an Event of Default occurs, Tenant owes Landlord, in
addition to all other amounts, Base Rent and Tenant's Pro Rata Share of
Operating Expenses abated pursuant to this paragraph during the Abatement Rent
Period. Tenant, however, has no obligation to pay the abated amounts if no Event
of Default occurs prior to the expiration of the Primary Term. Tenant shall pay
to Landlord as "Additional Rent" all other sums due under this Lease. Late
payments shall be subject to interest and penalties as set forth in Paragraph 19
hereof. In the event that the Premises are determined by Landlord's architect,
using its standard methodology for measuring the Building, to contain less than
21,539 rentable square feet, the Base Rent will be reduced pro rata.

     4.   Security Deposit: It is agreed that in the event Tenant is no longer
required to post the letter of credit provided for in Paragraph 42 of this Lease
or if the Lease is renewed at the end of the Term, that it shall, prior to the
termination of the letter of credit requirement, deposit with Landlord, and
thereafter keep on deposit at all times during the remainder of the term of the
Lease the sum of Forty-Nine Thousand Nine Hundred Twenty-Eight Dollars and
67/100 ($49,928.67), as security for the payment by Tenant of the Base Rent,
Additional Rent and all other sums herein agreed to be paid and for the Tenant's
performance of this Lease. If, at any time during the term hereof, Tenant shall
be in default in the performance of any provisions of this Lease, which default
has not been cured by Tenant, Landlord shall have the right, but shall not be
obligated, to use said deposit, or so much thereof as necessary, to compensate
Landlord for any loss damage, cost or expense (including reasonable attorney's
fees and costs) which Landlord may incur by reason of tenants uncured event of
default. If any part of the security deposit is so used or applied, Tenant shall
within five (5) days of written demand of Landlord, remit to Landlord a
sufficient amount in cash to restore said deposit to its original amount. In the
event said deposit has not been utilized said deposit, or as much thereof as has
not been utilized for such purposes, shall be refunded to Tenant, without
interest, after the termination of this Lease upon full performance of this
Lease by Tenant and vacation of the Premises by Tenant. Landlord shall have the
right to commingle said deposit with other funds of Landlord. Landlord may
deliver the funds deposited herein by Tenant to any purchaser of Landlord's
interest in the Premises in the event such interest is sold, and thereupon
Landlord shall be discharged from further liability with respect to such
deposit. If the claims of Landlord exceed the amount of said deposit, Tenant
shall remain liable for the balance of such claims.

     5.   Rent Adjustment:
          ---------------

          (a)  The following terms shall have the following meanings with
     respect to the provisions of this Paragraph 5:

                    (1)  "Expense Stop" shall mean an amount equal to $6.50 per
          rentable square foot of the Building.

                    (2)  "Operating Expense Differential" shall mean the
          difference between the Expense Stop and the actual Operating Expenses
          of the Building Complex on a per rentable square foot basis.

                    (3)  "Tenant's Operating Expense Differential" shall mean
          the Operating Expense Differential times the number of rentable square
          feet contained in the Premises.

                    (4)  "Building Rentable Area" shall mean all rentable space
          available for lease in the Building as set forth below. If there is a
          significant change in the aggregate Building Rentable

                                      -4-
<PAGE>

          Area, of a permanent nature, as a result of an addition to the
          Building, partial destruction thereof or similar circumstance,
          Landlord's architect and/or accountant shall determine and make an
          appropriate adjustment to the provisions herein.

                    (5)  "Premises Rentable Area" shall mean the total number of
          square feet of rentable area in the Premises as determined by
          Landlord's architect.

                    (6)  "Tenant's Pro Rata Share" shall mean a fraction, the
          numerator of which is the Premises Rentable Area (i.e., 21,398 square
          feet) and the denominator of which is the Building Rentable Area
          (i.e., 164,958 square feet), and is equal to 12.972%. At such time, if
          ever, any space is added to or subtracted from the Premises pursuant
          to the terms of this Lease, Tenants Pro Rata Share shall be increased
          or decreased accordingly.

                    (7)  "Operating Expenses" shall mean:

               (A)  All operating expenses of any kind or nature which are
necessary, ordinarily or customarily incurred with respect to the operation,
maintenance, repair and management of the Building Complex and generally charged
as an operating expense to tenants by landlords of comparable office buildings
in Denver, Colorado, and shall include, but not be limited to:

                              (ii)   Costs of supplies, including but not
                         limited to the cost of "relamping" all tenant lighting
                         as the same may be required from time to time;

                              (iii)  Costs incurred in connection with obtaining
                         and providing energy for the Building Complex,
                         including but not limited to costs of propane, butane,
                         natural gas, steam, electricity, solar energy and fuel
                         oils, coal or any other energy sources;

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

                              (v)    Costs of janitorial and security services,
                         if any;

                              (vi)   Costs of general maintenance and repairs,
                         including costs under heating, ventilation, and air
                         conditioning ("HVAC") and other mechanical maintenance
                         contracts; and repairs and replacements of equipment
                         used in connection with such maintenance and repair
                         work;

                              (vii)  Costs of maintenance and replacement of
                         landscaping; and costs of maintenance, repair of common
                         areas, plazas and other areas used by tenants of the
                         Building Complex, including trash and snow removal;

                              (viii) Insurance premiums, including fire and all-
                         risk property coverage, together with loss of rent
                         endorsement; commercial general liability insurance;
                         rental interruption insurance; and any other insurance
                         carried by Landlord on the Building Complex or any
                         component parts thereof;

                              (ix)   Labor costs, including wages and other
                         payments, costs to Landlord of workmen's compensation
                         and disability insurance, payroll taxes, welfare fringe
                         benefits and all legal fees and other costs or expenses
                         incurred in resolving any union labor disputes;

                              (x)    Building management fees (not to exceed the
                         amount paid to other third party managers of comparable
                         office buildings in the downtown Denver market area)
                         and all costs related to the provision of building
                         management services including the cost of office and
                         storage space;

                                      -5-
<PAGE>

                              (xi)   Reasonable legal, accounting, inspection
                         and other consultation fees incurred for the normal
                         prudent operation of the Building Complex;

                              (xii)  The costs of capital improvements and
                         structural repairs and replacements made in or to the
                         Building Complex or the cost of any machinery or
                         equipment installed in the Building Complex in order to
                         conform to changes, subsequent to the Lease
                         Commencement Date, in any applicable laws, ordinances,
                         rules, regulations or orders of any governmental or
                         quasi- governmental authority having jurisdiction over
                         Building Complex (herein, "Required Capital
                         Improvement"); and the costs of any capital
                         improvements and structural repairs and replacements
                         designed primarily to reduce Operating Expenses
                         (herein, "Cost Savings Improvements"). The expenditures
                         for Required Capital Improvements and Cost Savings
                         Improvements shall be amortized over the useful life of
                         such capital improvement or structural repair or
                         replacement (as determined by Landlord's accountants);
                         and

                              (xiii) "Real Estate Taxes" including all real
                         property taxes, assessments and fees levied against the
                         Building Complex by any governmental or quasi-
                         governmental authority or district (including any
                         historic or improvement district) and which are due and
                         payable during the Term, including any taxes,
                         assessments, surcharges, or service or other fees of a
                         nature not presently in effect which shall hereafter be
                         levied on the Building Complex as a result of the use,
                         ownership or operation of the Building Complex or for
                         any other reason, whether in lieu of or in addition to
                         any current real estate taxes, assessments, and fees;
                         provided, however, that any taxes which shall be levied
                         on the rentals of the Building Complex shall be
                         determined as if the Building Complex were Landlord's
                         only property and provided further, that in no event
                         shall the term "taxes, assessments, and fees", as used
                         herein, include any federal, state or local income
                         taxes levied or assessed on Landlord, unless such taxes
                         are a specific substitute for real property taxes.
                         "Assessments" shall include any and all so-called
                         special assessments, license tax, business license fee,
                         business license tax, commercial rental tax, levy,
                         charge or tax imposed by any authority or district
                         having the direct power to tax, including any city,
                         county, state or federal government, or any school,
                         agricultural, lighting, water, drainage or other
                         improvement or special district thereof, against the
                         Premises, the Building or the Building Complex, or
                         against any legal or equitable interest of Landlord
                         therein. For the purposes of this Lease, any special
                         assessment or fee shall be deemed payable in maximum
                         number of installments as is permitted by law, whether
                         or not actually so paid.

          (B)  Expressly excluded from Operating Expenses are the following:
                              (ii)   Landlord's income taxes;

                              (iii)  Leasing commissions, advertising and
                         promotional expenses incurred in the leasing of the
                         Building;

                              (iv)   Interest on debt or amortization payments
                         on any mortgages or deeds of trust;

                              (v)    Costs of repairs or other work occasioned
                         by fire, windstorm or other casualty to the extent of
                         insurance proceeds received;

                              (vi)   Depreciation;

                                      -6-
<PAGE>

                              (vii)  Any capital improvement other than those
                         specified as "Cost Saving Improvements" or "Required
                         Capital Improvements" in Paragraph 5(a)(4)(xi); and

                              (viii) Attorney's fees associated with customary
                         lease review and negotiation, and/or lease enforcement.

          (b)  It is hereby agreed that Tenant shall pay to Landlord as
     Additional Rent during each calendar year during the term hereof an
     estimate of Tenant's Operating Expense Differential as reasonably estimated
     by Landlord, payable monthly, at the rate of one twelfth (1/12) thereof, on
     the same date and at the same place Base Rent is payable, with an
     adjustment to be made between the parties at a later date as hereinafter
     provided; provided, however, that for the calendar year 2000 Tenant shall
     not be billed nor will it be required to pay any Operating Expense
     Differential. Furthermore, to the extent Tenant's Pro Rata Share of
     Operating Expense, during any year of the Term (annualized for a full
     twelve months) would have been less than $6.50 per rentable square foot,
     Tenant shall receive a credit for such amount against Tenant's Operating
     Expense Differential, if, and when it would otherwise be due and payable by
     Tenant or refunded to Tenant if no additional amounts are due from Tenant.
     Notwithstanding the foregoing sentence, Tenant shall not be entitled to any
     credit for any period during which the Base Rent is abated. Except for
     increases in real estate taxes, insurance and utilities, Landlord agrees
     that increases in the total Operating Expenses for which Tenant shall be
     obligated during the Term of this Lease will not increase more than five
     percent (5%) in any calendar year during the Term of this Lease over the
     immediately preceding calendar year; provided, however, that such
     percentage shall be increased by the unused portion of the five percent
     (5%) cap for the preceding years of the Term of the Lease. It is further
     agreed and understood that this shall only constitute a cap on the Tenant's
     share of Operating Expenses, other than real estate taxes, insurance and
     utilities which shall not be subject to the cap. Landlord shall deliver to
     Tenant, as soon as practicable following the end of each calendar year, an
     estimate of the Operating Expenses for the new calendar year (the "Budget
     Sheet"). Until receipt of the Budget Sheet, Tenant shall continue to pay
     its monthly Tenant's Operating Expense Differential based upon the estimate
     for the preceding calendar year. To the extent that the Budget Sheet
     reflects an estimate of Tenant's Operating Expense Differential for the new
     calendar year greater than the amount actually paid to the date of receipt
     of the Budget Sheet for the new calendar year, Tenant shall pay such amount
     to Landlord within thirty (30) days of receipt of the Budget Sheet. Upon
     receipt of the Budget Sheet, Tenant shall thereafter pay the amount of its
     monthly Tenant's Operating Expense Differential as set forth in the Budget
     Sheet. As soon as practicable following the end of any calendar year, but
     not later than May 1st, Landlord shall submit to Tenant a statement in
     reasonable detail describing the computations of the Operating Expenses,
     setting forth the exact amount of Tenant's Operating Expense Differential
     for the calendar year just completed (the "Statement"), and the difference,
     if any, between the actual Tenant's Operating Expense Differential for the
     calendar year just completed and the estimated amount of Tenant's Operating
     Expense Differential paid by Tenant to Landlord. Landlord's failure to
     deliver the Statement to Tenant on or before May 1st, shall in no way serve
     as a waiver of Landlord's rights under this Paragraph. To the extent that
     the actual Tenant's Operating Expense Differential for the period covered
     by the Statement is higher than the estimated Tenant's Operating Expense
     Differential which Tenant previously paid during the calendar year just
     completed, Tenant shall also pay to Landlord such balance within thirty
     (30) days following receipt of the Statement from Landlord. To the extent
     that the actual Tenant's Operating Expense Differential for the period
     covered by the Statement is less than the estimated Tenant's Operating
     Expense Differential which Tenant previously paid during the calendar year
     just completed, Landlord shall credit the excess against any sums then
     owing or next becoming due from Tenant under the Lease, or, if no
     additional sums are due, such amount shall be refunded to Tenant.

          In calculating the Operating Expenses and Tenant's Operating Expense
Differential, Landlord shall on an annual basis determine the proportionate
division of shared Operating Expenses between the Building and the retail
spaces. Shared Operating Expenses shall include, but not be limited to real
estate taxes, insurance, common areas, utilities, and HVAC, security, grounds
and landscaping, parking and exterior maintenance and life safety expenses.

                                      -7-
<PAGE>

          (c)  If the Lease term hereunder covers a period of less than a full
     calendar year during the first or last calendar years of the term hereof,
     the Expense Stop and Tenant's Operating Expense Differential for such
     partial year shall be calculated by proportionately reducing each to
     reflect the number of months in such year during which Tenant leased the
     Premises.

          (d)  Tenant shall have the right at its own expense and at a
     reasonable time (after written notice to Landlord) within sixty (60) days
     after receipt of the Statement to review Landlord's books relevant to the
     Additional Rent due under this Paragraph 5; provided, however, that Tenant
     may not employ any firm or individual to review Landlord's books which is
     compensated on any form of contingent fee basis. In the event Tenant does
     not review Landlord's books and deliver the results thereof to Landlord
     within said 60- day period, the terms and amounts set forth in the
     Statement shall be deemed conclusive and final and Tenant shall have no
     further right to adjustment. In the event Tenant's examination reveals that
     an error has been made in Landlord's determination of Tenant's Operating
     Expense Differential and Landlord agrees with such determination, then the
     amount of such adjustment shall be payable by Landlord or Tenant, to the
     other party as the case may be. In the event Tenant's examination reveals
     an error has been made in Landlord's determination of Tenant's Operating
     Expense Differential, and Landlord disagrees with the results thereof,
     Landlord shall have thirty (30) days to obtain a review from an accountant
     of its choice to determine Tenant's Operating Expense Differential. In the
     event Landlord's accountant and Tenant's accountant are unable to reconcile
     their reviews, both accountants shall mutually agree upon a third
     accountant, whose determination of Tenant's Operating Expense Differential
     shall be conclusive.

          (e)  Landlord's failure during the Lease term to prepare and deliver
     any statements or bills, or Landlord's failure to make a demand under this
     Paragraph or under any other provision of this Lease shall not in any way
     be deemed to be a waiver of, or cause Landlord to forfeit or surrender its
     rights to collect any items of Additional Rent which may have become due
     pursuant to this Paragraph during the term of this Lease. Tenant's
     liability for all Additional Rent due under this Paragraph 5 shall survive
     the expiration or earlier termination of this Lease.

          (f)  If at any time during the term of this Lease, the occupancy area
     of the Building leased to tenants is less than 95% of the capacity, then
     for purposes of calculating Operating Expenses, those Operating Expenses
     that vary with occupancy shall be grossed up to reflect Building occupancy
     of 95%. For purposes of calculating Operating Expenses, Real Estate Taxes
     shall be included in an amount equal to the actual amount paid by the
     Landlord for the year in question.

     6.   Character of Occupancy:
          ----------------------

          (a)  The Premises are to be used for general offices not inconsistent
     with the character and type of tenancy found in comparable first-class
     office buildings in the Denver metropolitan area and for no other purpose
     without the prior written consent of Landlord, which consent shall not be
     unreasonably withheld.

          (b)  Tenant shall not suffer nor permit the Premises nor any part
     thereof to be used in any manner, nor anything to be done therein, nor
     suffer or permit anything to be brought into or kept therein, which would
     in any way (i) make void or voidable any fire or liability insurance policy
     then in force with respect to the Building Complex, (ii) make unobtainable
     from insurance companies authorized to do business in Colorado any fire
     insurance with extended coverage, or liability, elevator, boiler or other
     insurance required to be furnished by Landlord under the terms of any lease
     or mortgage to which this Lease is subordinate at standard rates, (iii)
     cause or in Landlord's reasonable opinion be likely to cause physical
     damage to the Building Complex or any part thereof, (iv) constitute a
     public or private nuisance, (v) impair, in the opinion of Landlord, the
     appearance, character or reputation of the Building Complex, (vi) discharge
     objectionable fumes, vapors or odors into the Building air conditioning
     system or into the Building flues or vents not designed to receive them or
     otherwise in such manner as may unreasonably offend other occupants of the
     Building, (vii) impair or interfere with any of the Building services or
     impair or interfere with or tend to impair or interfere with the use of any
     of the other areas of the Building by, or occasion discomfort, or annoyance
     to Landlord or any of the other tenants or occupants of the Building


                                      -8-
<PAGE>

     Complex, any such impairment or interference to be based upon the judgment
     of Landlord, (viii) increase on an ongoing periodic basis the pedestrian
     traffic in and out of the Premises or the Building above an ordinary level,
     (ix) create waste in, on or around the Premises, Building, or Building
     Complex, or (x) make any noise or set up any vibration which will disturb
     other tenants, except in the course of permitted repairs or alterations at
     times permitted by Landlord.

          (c)  Tenant shall not use the Premises nor permit anything to be done
     in or about the Premises or Building Complex which will in any way conflict
     with any law, statute, ordinance, protective covenants affecting the
     Building Complex or governmental or quasi-governmental rules or regulations
     now in force or which may hereafter be enacted or promulgated. Tenant shall
     give written notice within two (2) days from receipt thereof to Landlord of
     any notice it receives of the violation of any law or requirement of any
     public authority with respect to the Premises or the use or occupation
     thereof. Landlord shall give prompt notice to Tenant of any notice it
     receives relative to the violation by Tenant of any law or requirement of
     any public authority with respect to the Premises or the use or occupation
     thereof.

     7.   Services and Utilities:
          ----------------------

          (a)  Landlord agrees, without charge except as provided herein, to
     furnish water to the Building for use in lavatories and drinking fountains
     (and to the Premises if the plans for the Premises so provide); during
     Ordinary Business Hours (hereinafter defined) to furnish such heated or
     cooled air to the Premises as may, in the judgment of Landlord, be
     reasonably required for the comfortable use and occupancy of the Premises
     provided that Tenant complies with the recommendations of Landlord's
     engineer or other duly authorized representative, regarding occupancy and
     use of the Premises; to provide janitorial services for the Premises
     (including such interior and exterior window washing as may be required),
     such janitorial services to be provided five (5) days a week, except for
     "Holidays" as (hereinafter defined); during Ordinary Business Hours to
     cause electric current to be supplied for lighting the Premises and public
     halls; and to furnish such snow removal services to the Building Complex as
     may, in the judgment of Landlord, be reasonably required for safe access to
     the Building Complex.

          (b)  Landlord shall furnish to the Premises electricity during
     Ordinary Business Hours for Building standard connected load in an average
     amount of eight (8.0) watts per square foot of rentable area within the
     Premises which includes the following: (i) two (2) watts per square foot of
     rentable area within the Premises for ceiling lighting; and (ii)
     approximately six (6) watts per square foot of rentable area within the
     Premises for general purpose power (which includes two (2.0) watts for PC
     rated power). Landlord shall provide Tenant with an average of 4.2 watts on
     a demand load basis per square foot of rentable area in the Premises;
     provided, that Tenant may, at its sole cost and expense, augment the
     existing equipment in order to provide additional watts on a demand load
     basis. Under such circumstances Tenant shall install at its sole cost and
     expense a demand meter to measure Tenant's actual electricity consumption
     and Tenant shall pay for all electricity consumption which is in excess of
     the Building standard. The cost of any electrical service at (i) other than
     Ordinary Business Hours and (ii) during Ordinary Business Hours but
     exceeding the above specified wattage, whether determined by separate
     metering or survey as set forth hereinafter, (the Excess Electricity) shall
     be paid pursuant to Paragraph 7(c) as Additional Rent. Nothing herein shall
     be deemed to create any obligation of Landlord to provide electrical
     equipment in excess of that expressly set forth in this Paragraph 7(b).
     Ordinary Business Hours shall mean from 7:00 a.m. to 6:00 p.m. weekdays and
     from 8:00 a.m. to 1:00 p.m. Saturdays (Sundays and Holidays excepted).

          (c)  At any time and from time to time, Landlord may conduct
     electrical surveys within the Premises to determine Tenant's consumption of
     Excess Electricity, if any. If such survey(s) shall reveal usage by Tenant
     of Excess Electricity, Tenant shall pay Landlord for such Excess
     Electricity, at Landlord's average cost for the same per kilowatt hour
     (KWH) (determined by dividing Landlord's total monthly cost for electricity
     by the total number of KWHs consumed in the Building during the
     corresponding month) upon monthly invoice for the same from Landlord. Said
     invoices shall be deemed and paid as Additional Rent.

                                      -9-
<PAGE>

          (d)  Landlord shall have the right, if it determines based on its own
     judgment that Tenant is using electric current for purposes other than
     those described above or Excess Electricity, to require Tenant to install a
     check meter to determine the amount which Tenant is utilizing. The cost of
     such Excess Electricity, and check meter, including but not limited to
     monitoring, installation and repair thereof, shall be paid by Tenant.

          (e)  Tenant agrees that Landlord shall not be liable for failure to
     supply any heating, air conditioning, elevator, electrical, janitorial,
     lighting or other services during any period when Landlord uses reasonable
     diligence to supply such services, or during any period Landlord is
     required to reduce or curtail such services pursuant to any applicable
     laws, rules or regulations, now or hereafter in force or effect, it being
     understood and agreed to by Tenant that Landlord may discontinue, reduce or
     curtail such services, or any of them at such times as it may be necessary
     by reason of accident, repairs, alterations, improvements, strikes,
     lockouts, riots, acts of God, application of applicable laws, statutes,
     rules and regulations, or due to any other happening beyond the reasonable
     control of Landlord. In the event of any such interruption, reduction or
     discontinuance of Landlord's services due to events beyond its reasonable
     control, Landlord shall not be liable for damages to persons or property as
     a result thereof, nor shall the occurrence of any such event in any way be
     construed as an eviction of Tenant or cause or permit an abatement,
     reduction or setoff of rent, or operate to release Tenant from any of
     Tenant's obligations hereunder. Notwithstanding anything to the contrary
     contained in this Paragraph 7(e) if: (i) Landlord ceases to furnish any
     service in the Building for a period in excess of five (5) consecutive
     business days after Tenant notifies Landlord of such cessation; (ii) such
     cessation does not arise as a result of an act or omission of Tenant; (iii)
     such cessation is not caused by a fire or other casualty (in which case
     Article 15 shall control); (iv) the restoration of such service is
     reasonably within the control of Landlord; and (v) as a result of such
     cessation, the Premises, or a material portion thereof, is rendered
     untenantable (meaning that Tenant is unable to use the Premises or such
     portion in the normal course of its business) and Tenant in fact ceases to
     use the Premises, or material portion thereof, then Tenant, as its sole
     remedy, shall be entitled to receive an abatement of Base Rent and any
     Operating Expense Differential payable hereunder during the period
     beginning on the sixth (6th) consecutive business day of such cessation and
     ending on the day when the service in question has been restored. In the
     event the entire Premises has not been rendered untenantable by the
     cessation in service, the amount of abatement that Tenant is entitled to
     receive shall be prorated based upon the percentage of the Premises so
     rendered untenantable and not used by Tenant.

          (f)  Whenever heat generating machines or equipment are used by Tenant
     in the Premises which affect the temperature otherwise maintained by the
     air conditioning system, Landlord reserves the right to install
     supplementary air conditioning units in the Premises in the event
     Landlord's independent consulting engineer determines same are necessary as
     a result of Tenant's use of lights or equipment which generate heat loads
     in excess of those for which the HVAC system is designed and the cost
     therefor, including the cost of installation, operation and maintenance
     thereof, shall be paid by Tenant to Landlord upon demand by Landlord.

          (g)  In the event that Tenant has any special or additional electrical
     or mechanical requirements related to its use of the Premises, any such
     electrical or mechanical equipment must be located within the Premises.
     Such electrical or mechanical requirements, for the purposes hereof, shall
     include by way of example, but not limitation, any internal telephone
     system. The foregoing shall in no way be construed as granting to Tenant
     additional rights to use any such special or additional electrical or
     mechanical equipment in its Premises without the prior written consent of
     Landlord. Any additional cost or expense related to or resulting from such
     electrical or mechanical requirements shall be the sole obligation of
     Tenant.

          (h)  If Tenant requires HVAC service beyond Ordinary Business Hours
     (hereafter "After Hours Usage"), such service shall be metered and Tenant
     shall reimburse Landlord on a monthly basis, as Additional Rent, for all
     costs and expenses for Tenant's After Hours Usage including Landlord's
     actual cost for electric service without markup.

                                      -10-
<PAGE>

     8.   Quiet Enjoyment. Subject to the provisions of this Lease, Landlord
          ---------------
covenants that Tenant on paying the rent and performing the covenants of this
Lease on its part to be performed shall and may peacefully and quietly have,
hold and enjoy the Premises for the Term of this Lease. Landlord shall not be
responsible for the acts or omissions of any other tenant or third party which
may interfere with Tenant's use and enjoyment of the Premises.

     9.   Maintenance and Repairs; Building Management:
          --------------------------------------------

          (a)  Notwithstanding any other provisions of this Lease, Landlord
     shall repair and maintain the structural portions of the Building,
     including the elevators, plumbing, air conditioning, heating and electrical
     systems installed or furnished by Landlord, except to the extent such
     maintenance and repairs are caused by the act, neglect, fault or omission
     of Tenant, its agents, servants, employees, licensees or invitees, in which
     case Tenant shall pay to Landlord, on demand, the cost of such maintenance
     and repairs less the amount of any insurance proceeds received by Landlord
     on account thereof, if applicable. Landlord shall also maintain and keep in
     good order and repair the Building roof; the curtain wall, including all
     glass connections at the perimeter of the Building; all exterior doors,
     including any exterior plate glass within the Building; the Building
     ventilating systems; elevators; escalators; Building telephone and
     electrical closets; public portions of the Building or Building Complex,
     including but not limited to the balconies, landscaping, walkways, upper
     floor lobbies and corridors, the parking garage and interior portions of
     the Building above and below grade which are not covered by leases.
     Landlord or its property manager shall manage the Building in a first class
     manner and shall use its reasonable efforts to do so in a cost effective
     and competitive manner while still maintaining the quality of the Building.

          (b)  Tenant, at Tenant's sole cost and expense, except for services
     furnished by Landlord pursuant to Paragraph 7 hereof, shall maintain, in
     good order, condition and repair, the Premises, including the interior
     surfaces of the ceiling (if damaged or discolored due in whole or in part
     to the act, neglect, omission or fault of Tenant), walls and floors, all
     doors, interior glass partitions of glass surfaces (not exterior windows)
     and pipes, electrical wiring, switches, fixtures and other special items,
     subject to the provisions of Paragraph 15 hereof In the event Tenant fails
     to so maintain the Premises in good order, condition and repair, Landlord
     shall give Tenant notice to do such acts as are reasonably required to
     maintain the Premises. In the event Tenant fails to promptly commence such
     work and diligently pursue it to completion, then Landlord shall have the
     right, but shall not be required, to do such acts and expend such funds at
     the expense of the Tenant as are reasonably required to perform such work.
     Landlord shall have no liability to Tenant for any damage, inconvenience or
     interference with the use of the Premises by Tenant as a result of
     performing any such work.

          (c)  Tenant and Landlord shall do all acts required to comply with all
     applicable laws, ordinances, regulations and rules of any public authority
     relating to their respective maintenance obligations as set forth herein.
     Landlord and Tenant acknowledge that the requirements of the Americans with
     Disabilities Act (ADA) are and will be subject to various and possibly
     contradictory interpretations. Tenant acknowledges, therefore, that the
     Landlord and its architects and contractors making Tenant Improvements to
     the Building will use their best professional efforts to interpret
     applicable statutes, ordinances, and regulations as they apply to the
     Building. The Landlord, however, cannot and does not warrant or guarantee
     that the Building complies with all interpretations to the ADA
     requirements, but will use its reasonable efforts to effect such
     compliance.

          (d)  Whenever a special HVAC System is installed in all or part of the
     Premises, Tenant shall enter into a regularly scheduled preventative
     maintenance and service contract, at Tenant's sole cost and expense, with
     an experienced maintenance and service contractor for servicing all such
     heating, air conditioning and ventilation systems and equipment, and shall
     provide Landlord with a copy of the same. The contractor and contract are
     both subject to Landlord's prior approval, which approval will not be
     unreasonably withheld or delayed. Such contract shall include, at a
     minimum, all services recommended by the equipment manufacturer and must be
     effective within thirty (30) days of the Commencement Date

                                      -11-
<PAGE>

     hereof. Landlord shall retain all manufacturers' warranty information, if
     any, and will cooperate with the Tenant to the extent warranty repairs are
     required.

          10.  Alterations and Additions:
               -------------------------

               (a)  Tenant shall make no alterations, additions or improvements
     to the Premises or any part thereof without obtaining the prior written
     consent of Landlord, which consent may be withheld in Landlord's sole
     discretion, provided, however, that Landlord will not unreasonably withhold
     or delay its consent to alterations or improvements which do not effect the
     structural, mechanical or operating components of the Building. Tenant
     shall submit any such request to Landlord at least thirty (30) days prior
     to the proposed commencement date of such work. Landlord may impose, as a
     condition to such consent, such requirements as Landlord may deem necessary
     in its reasonable judgment, including without limitation, the manner in
     which the work is done, a right of approval of the contractor by whom the
     work is to be performed and the times during which the work is to be
     accomplished, approval of all plans and specifications and the procurement
     of all licenses and permits. Landlord shall be entitled to post notices on
     and about Premises with respect to Landlord's non-liability for mechanics'
     liens and Tenant shall not permit such notices to be defaced or removed.
     Tenant further agrees not to connect any apparatus, machinery or device to
     the Building systems, including electric wires, water pipes, fire safety,
     heating and mechanical systems, without the prior written consent of
     Landlord. Upon completion Tenant shall furnish Landlord "as built" plans,
     contractor's affidavits and full and final lien waivers and receipted bills
     covering all labor and materials. Tenant shall reimburse Landlord upon
     demand as Additional Rent for all sums, if any, incurred by Landlord for
     examination of Tenant's architectural, mechanical, electrical and plumbing
     plans and construction supervision for any such alterations, additions or
     improvements.

          (b)  All alterations, improvements and additions to the Premises,
     including, by way of illustration but not by limitation, all counters,
     screens, grilles, special cabinetry work, partitions, paneling, carpeting,
     drapes or other window coverings and light fixtures, shall be deemed a part
     of the real estate and the property of Landlord and shall remain upon and
     be surrendered with the Premises as a part thereof without molestation,
     disturbance or injury at the end of the Lease term, whether by lapse of
     time or otherwise; provided that Landlord, may, at its option, at the time
     consent is given to the alteration, improvement or alteration, require
     Tenant to remove all or any of such alterations, improvements (including
     data and telephone cabling) or additions (excluding non-movable office
     walls), and in such event, Tenant shall promptly remove, at its sole cost
     and expense, such alterations, improvements and additions and restore the
     Premises to the condition in which the Premises were prior to the making of
     the same, reasonable wear and tear excepted. Any such removal, whether
     required or permitted by Landlord, shall be at Tenant's sole cost and
     expense, and Tenant shall restore the Premises to the condition in which
     the Premises were prior to the making of the same, reasonable wear and tear
     excepted. All movable partitions, machines and equipment which are
     installed in the Premises by or for Tenant, without expense to Landlord,
     and can be removed without structural damage to or defacement of the
     Building or the Premises, and all furniture, furnishings and other articles
     of personal property owned by Tenant and located in the Premises (all of
     which are herein called "Tenant's Property") shall be and remain the
     property of Tenant and may be removed by it at any time during the term of
     this Lease. However, if any of Tenant's Property is removed, Tenant shall
     repair or pay the cost of repairing any damage to the Building or the
     Premises resulting from such removal, including any holes or damages to the
     drywall. All additions or improvements which are to be surrendered with the
     Premises shall be surrendered with the Premises, as a part thereof, at the
     end of the term or the earlier termination of this Lease.

          (c)  If Landlord permits persons requested by Tenant to perform any
     alterations, repairs, modifications or additions to the Premises, then
     prior to the commencement of any such work, Tenant shall deliver to
     Landlord certificates issued by insurance companies qualified to do
     business in the State of Colorado evidencing that worker's compensation,
     commercial general public liability insurance and property damage
     insurance, all in amounts, with companies and on forms satisfactory to
     Landlord, are in force and maintained by all such contractors and
     subcontractors engaged by Tenant to perform such work.

                                      -12-
<PAGE>

     All such policies shall name Landlord as an additional insured and shall
     provide that the same may not be canceled or modified without thirty (30)
     days prior written notice to Landlord.

          (d)  Tenant, at its sole cost and expense, shall cause any permitted
     alterations, decorations, installations, additions or improvements in or
     about the Premises to be performed in compliance with all applicable codes,
     ordinances, laws (including the Americans with Disabilities Act),
     regulations and requirements of governmental bodies having jurisdiction and
     insurance companies insuring the Building, and in such manner as not to
     interfere with, delay, or impose any additional expense upon Landlord in
     the construction, maintenance or operation of the Building, and so as to
     maintain harmonious labor relations in the Building.

     11.  Entry by Landlord:
          -----------------

          (a)  Landlord and its agents shall have the right to enter the
     Premises at all reasonable times upon reasonable notice (except in the case
     of an emergency) for the purpose of examining or inspecting the same, to
     supply any services to be provided by Landlord hereunder, to show the same
     to prospective purchasers of the Building, to make such alterations,
     repairs, improvements or additions to the Premises or to the Building as
     Landlord may deem necessary or desirable, and during the last nine (9)
     months of the Term to show the same to prospective tenants of the Premises.
     Landlord and its agent may enter the Premises at all times and without
     advance notice for the purpose of responding to an actual or apparent
     emergency. Landlord may for the purpose of supplying scheduled janitorial
     services and evaluating janitorial services at any time and from time to
     time enter the Premises by means of a master key without liability to
     Tenant and without affecting this Lease. If, during the last 60 days of the
     term hereof, Tenant shall have removed substantially all of its property
     from the Premises, Landlord may immediately enter and alter, renovate and
     redecorate the Premises without elimination or abatement of rent or
     incurring liability to Tenant for any compensation.

          (b)  Tenant shall be entitled to one Building access card for each
     employee and two (2) sets of standard lockset keys to the Premises. In the
     event Tenant needs any additional access cards or keys, such keys must be
     requested from Landlord. Tenant shall pay to Landlord the actual cost of
     making such additional access cards and keys.

     12.  Mechanic's Liens: Tenant shall pay or cause to be paid all costs for
          ----------------
work done by or on behalf of Tenant or caused to be done by or on behalf of
Tenant on the Premises of a character which will or may result in liens against
Landlord's interest in the Premises, Building or Building Complex and Tenant
will keep the Premises, Building and Building Complex free and clear of all
mechanic's liens and other liens on account of work done for or on behalf of
Tenant or persons claiming under Tenant. Tenant hereby agrees to indemnify,
defend and save Landlord harmless of and from all liability, loss, damages,
costs or expenses, including attorneys' fees, incurred in connection with any
claims of any nature whatsoever for work performed for, or materials or supplies
furnished to Tenant, including lien claims of laborers, materialmen or others.
Should any such liens be filed or recorded against the Premises, Building or
Building Complex with respect to work done for or materials supplied to or on
behalf of Tenant or should any action affecting the title thereto be commenced,
Tenant shall cause such liens to be released of record within twenty (20) days
after notice thereof. If Tenant desires to contest any such claim of lien,
Tenant shall nonetheless cause such lien to be released of record by the posting
of adequate security within said five (5) day period with a court of competent
jurisdiction as may be provided by Colorado's mechanic lien statutes. If Tenant
shall be in default in paying any charge for which such a mechanic's lien or
suit to foreclose such a lien has been recorded or filed and shall not have
caused the lien to be released as aforesaid, Landlord may (but without being
required to do so) pay such lien or claim and any costs associated therewith,
and the amount so paid, together with reasonable attorneys' fees incurred in
connection therewith, shall be immediately due from Tenant to Landlord as
Additional Rent.

                                      -13-
<PAGE>

     13.  Damage to Property; Injury to Persons:
          -------------------------------------

               (a)  Tenant, as a material part of the consideration to be
          rendered to Landlord under this Lease, hereby waives all claims of
          liability that Tenant or Tenant's legal representatives, successors or
          assigns may have against Landlord, and Tenant hereby indemnifies and
          agrees to hold Landlord harmless from any and all claims of liability
          for any injury or damage to any person or property whatsoever: (I)
          occurring in, on or about the Premises or any part thereof, except to
          the extent the same arises out of the negligence of the Landlord, its
          agents, contractors or employees; and (2) occurring in, on or about
          the Building Complex, to the extent such injury or damage is caused in
          part or in whole by the act, neglect, fault or omission of Tenant, its
          agents, contractors, employees, licensees or invitees. Tenant further
          agrees to indemnify and to hold Landlord harmless from and against any
          and all claims arising from any breach or default in the performance
          of any obligation on Tenant's part to be performed under the terms of
          this Lease, or arising from any act or negligence of Tenant, or any of
          its agents, contractors, employees, licensees or invitees. Such
          indemnities shall include by way of example, but not limitation, all
          costs, reasonable attorneys' fees, expenses and liabilities incurred
          in or about any such claim, action or proceeding.

               (b)  Landlord shall not be liable to Tenant for any damage by or
          from any act or negligence of any co-tenant or other occupant of the
          Building Complex, or by any owner or occupant of adjoining or
          contiguous property. Landlord shall not be liable for any injury or
          damage to persons or property resulting in whole or in part from the
          criminal activities of others. To the extent not covered by normal and
          customary fire and extended coverage insurance maintained by Landlord
          or by prudent building owners in the Denver, Colorado area, and not
          otherwise caused by the negligence of Landlord, its agents,
          contractors or employees, Tenant agrees to pay for all damage to the
          Building Complex, as well as all damage to persons or property of
          other tenants or occupants thereof, caused by the misuse, neglect,
          act, omission or negligence of Tenant or any of its agents,
          contractors, employees, licensees or invitees.

               (c)  Neither Landlord nor its agents or employees shall be liable
          for any damage to property entrusted to Landlord, its agents or
          employees, or employees of the building manager, if any, nor for the
          loss or damage to any property occurring by theft or otherwise, nor
          for any injury or damage to persons or property resulting from fire,
          explosion, falling plaster, steam, gas, electricity, water of rain
          which may leak from any part of the Building Complex or from the
          pipes, appliances or plumbing works therein or from the roof, street
          or subsurface or from any other place or resulting from dampness, or
          any other cause whatsoever; provided, however, nothing contained
          herein shall be construed to relieve Landlord from liability for any
          personal injury resulting from its negligence or willful misconduct or
          its breach of its obligations under this Lease. Neither Landlord nor
          its agents or employees shall be liable for interference with the
          lights, view or other incorporeal hereditament. Tenant shall give
          prompt notice to Landlord in case of fire or accidents in or about the
          Premises or the Building or of defects therein or in the fixtures or
          equipment located therein.

               (d)  In case any claim, demand, action or proceeding is made or
          brought against Landlord, its agents or employees, by reason of any
          obligation on Tenant's part to be performed under the terms of this
          Lease, or arising from any act or negligence of Tenant, its agents or
          employees, or which gives rise to Tenant's obligation to indemnify
          Landlord, Tenant shall be responsible for all costs and expenses,
          including but not limited to reasonable attorneys' fees incurred in
          defending or prosecution of the same, as applicable.

          14.  Insurance:
               ---------

               (a)  Landlord agrees to secure and maintain the following
          insurance during the term of this Lease and any extension hereof:
          commercial general public liability insurance against claims for
          bodily injury, personal injury and property damage in or about the
          Premises, the Building and the Building Complex (excluding Tenant's
          Property), such insurance to be in amounts sufficient to provide
          reasonable protection for the Building Complex. Landlord shall also
          secure and maintain "all risk" property insurance on the Building and
          Building Complex. Such insurance may expressly exclude property paid
          for by tenants or

                                      -14-
<PAGE>

          paid for by Landlord for which tenants have Landlord located in or in,
          or constituting a part of the Building or the Building Complex. All
          such insurance shall be procured from a responsible insurance company
          or companies authorized to do business in Colorado and may be obtained
          by Landlord by endorsement on its blanket insurance policies.

               (b)  Tenant (with respect to the Premises, the Building and the
          Building Complex) shall secure and maintain, at its own expense, a
          policy or policies of commercial general liability insurance with the
          premiums thereon fully paid in advance, protecting Tenant and naming
          Landlord, its property manager and their respective agents as
          additional insured against claims for bodily injury, personal injury,
          advertising injury and property damaged based upon, involving or
          arising out of the Tenant's use, occupancy or maintenance of the
          Premises, the Building and the Building Complex. Such insurance shall
          afford a combined single limit of not less than One Million Dollars
          ($1,000,000) per occurrence and aggregate of Two Million Dollars
          ($2,000,000). Any general aggregate shall apply on a per location
          basis. The coverage required to be carried shall include blanket
          contractual liability, personal injury liability (libel, slander,
          false arrest and wrongful eviction), and broad form property damage
          liability and the policy shall contain an exception to any pollution
          exclusion which insures damage or injury arising out of heat, smoke or
          fumes from a hostile fire. Such insurance shall be written on an
          occurrence basis and contain a standard separation of insureds
          provision. Tenant shall secure and maintain at its expense business
          auto liability insurance which insures against bodily injury and
          property damage claims arising out of the ownership, maintenance and
          use of any auto with a minimum combined single limit per accident of
          One Million Dollars ($1,000,000). In addition, Tenant shall secure and
          maintain workers' compensation and employer's liability insurance with
          limits of Five Hundred Thousand Dollars ($500,000) per accident, Five
          Hundred Thousand Dollars ($500,000) per employee for bodily injury by
          disease with a Five Hundred Thousand Dollar ($500,000) policy limit
          for bodily injury by disease, and all such other insurance as may be
          required by applicable law. Tenant shall provide Landlord with a
          certificate evidencing such insurance coverage. The certificate shall
          indicate that the insurance provided specifically recognizes the
          liability assumed by Tenant under this Lease and that Tenant's
          insurance is primary to and not contributory with any other insurance
          available to Landlord, whose insurance shall be considered excess
          insurance only. Not more frequently than every three years, if, in the
          opinion of any mortgagee of Landlord or of the insurance broker
          retained by Landlord, the amount of liability insurance coverage at
          that time is not adequate, then Tenant shall increase its liability
          insurance coverage as required by either any mortgagee of Landlord or
          Landlord's insurance broker.

               (c)  Tenant shall secure and maintain, at Tenant's expense,
          special form fire and extended coverage insurance on all of Tenant's
          fixtures and personal property in the Premises and on any improvements
          or alterations, additions or improvements made by Tenant, upon the
          Premises, in an amount determined by Tenant (or such other form of
          property insurance then available in the insurance market that is most
          comparable or equivalent to "all risk"). Tenant shall provide Landlord
          with certificates of all such insurance. The property insurance
          certificate shall confirm that the waiver of subrogation required to
          be obtained pursuant to Paragraph 14(g) is permitted by the insurer.
          Tenant shall, at least thirty (30) days prior to the expiration of any
          policy of insurance required to be maintained by Tenant under this
          Lease, furnish Landlord with an "insurance binder" or other
          satisfactory evidence of renewal thereof.

               (d)  All policies required to be carried by Tenant hereunder
          shall be issued by and binding upon an insurance company licensed to
          do business in the State of Colorado with a rating of at least A-
          :VIII, or such other rating as may be required by a lender having a
          lien on the Building as set forth in the then most current issue of
          "Best's Insurance Reports." Tenant shall not do or permit anything to
          be done that would invalidate the insurance policies referred to in
          this Paragraph 14. Evidence of insurance provided to Landlord shall
          include an endorsement showing that Landlord and its representatives
          are included as additional insureds on general liability insurance,
          and an endorsement whereby the insurer agrees not to cancel, non-renew
          or reduce coverage of the policy without at least thirty (30) days
          prior written notice to Landlord and its representatives.

                                      -15-
<PAGE>

               (e)  In the event that Tenant falls to provide evidence of
          insurance required to be provided by Tenant hereunder, prior to
          commencement of the Term, and thereafter during the Term, within ten
          (10) days following Landlord's request therefor, and thirty (30) days
          prior to the expiration date of any such coverage, Landlord shall be
          authorized (but not required) to procure such coverage in the amounts
          stated with all costs thereof (plus a fifteen percent [15%]
          administrative fee) to be chargeable to Tenant and payable upon
          written invoice therefor.

               (f)  The limits of insurance required by this Lease, or as
          carried by Tenant, shall not limit the liability of Tenant nor relieve
          Tenant of any obligation hereunder.

               (g)  Anything in this Lease to the contrary notwithstanding,
          Landlord and Tenant each waives all rights of recovery, claim, action
          or cause of action against the other, its agents (including partners,
          both general and limited), trustees, officers, directors, and
          employees, for any loss or damage that may occur to the Premises, or
          any improvements thereto, or the Building or any personal property of
          such party therein, by reason of any cause required to be insured
          against under this Lease, regardless of cause or origin, including
          negligence of the other party hereto and each party agrees to look
          solely to its insurance coverage in the event of such loss; and each
          party covenants that, to the fullest extent permitted by law, no
          insurer shall hold any right to subrogation against such other party.
          Tenant shall advise its insurers of the foregoing and such waiver
          shall be a part of each Tenant policy maintained by which applies to
          the Premises, any part of the Building or Tenant's use and occupancy
          of any part thereof.

               (h)  Any Building employee to whom property shall be entrusted by
          or on behalf of Tenant shall be deemed to be acting as Tenant's agent
          with respect to such property and neither Landlord, the Building
          manager, if any, nor their respective agents shall be liable for any
          damage to the property of Tenant or others entrusted to employees of
          the Building, nor for the loss of or damage to any such property by
          theft or otherwise and Tenant shall indemnify Landlord of and from any
          loss or damages, costs or actions Landlord may suffer or incur as a
          result of such loss or damage to Property.

          15.  Damage or Destruction to Building:
               ---------------------------------

               (a)  In the event that the Premises or the Building are damaged
          by fire or other insured casualty and the insurance proceeds have been
          made available therefor by the holder or holders of any mortgages or
          deeds of trust covering the Building, the damage shall be repaired by
          and at the expense of Landlord to the extent of such insurance
          proceeds available therefor cover at least 95% of the cost of repair,
          provided such repairs and restoration can, in Landlord's reasonable
          opinion, be made within one hundred eighty (180) days after the
          occurrence of such damage without the payment of overtime or other
          premiums, and until such repairs and restoration are completed, the
          Base Rent and Tenant's Operating Expense Differential shall be abated
          in proportion to the part of the Premises which is unusable by Tenant
          in the conduct of its business, as may be reasonably determined by
          Landlord and Tenant, (but there shall be no abatement of Base Rent by
          reason of any portion of the Premises being unusable for a period
          equal to one day or less). Landlord agrees to notify Tenant within
          sixty (60) days after such casualty if it estimates that it will be
          unable to repair and restore the Premises within said one hundred
          eighty (180) day period. Such notice shall set forth the approximate
          length of time Landlord estimates will be required to complete such
          repairs and restoration. Notwithstanding anything to the contrary
          contained herein, if Landlord cannot or estimates it cannot make such
          repairs and restoration within said one hundred eighty (180) day
          period, then Tenant may, by written notice to Landlord cancel this
          Lease, provided such notice is given to Landlord within fifteen (15)
          days after Landlord notifies Tenant of the estimated time for
          completion of such repairs and restoration. In any event, if Landlord
          is unable to complete the repairs and restoration within two hundred
          ten (210) days after the casualty, Tenant may terminate this Lease by
          giving Landlord written notice of cancellation within fifteen (15)
          days after the expiration of the two hundred ten (210) day period.
          Except as provided in this Paragraph 15, there shall be no abatement
          of rent and no liability of Landlord by reason of any injury to or
          interference with Tenant's business or property arising from the
          making of any such repairs, alterations or improvements in or to the
          Building, Premises or fixtures, appurtenances and equipment. Tenant
          understands that Landlord will not carry insurance of any kind on
          Tenant's property,

                                      -16-
<PAGE>

          including furniture and furnishings, or on any fixtures or equipment
          removable by Tenant under the provisions of this Lease, or any
          improvement installed in the Premises by or on behalf of Tenant, and
          that Landlord shall not be obligated to repair any damage thereto or
          replace the same.

               (b)  In case the Building throughout shall be so injured or
          damaged, whether by fire or otherwise (though the Premises may not be
          affected, or if affected, can be repaired within said 180 days) that
          Landlord, within sixty (60) days after the happening of such injury,
          shall decide not to reconstruct or rebuild the Building, then
          notwithstanding anything contained herein to the contrary, upon notice
          in writing to that effect given by Landlord to Tenant within said
          sixty (60) days, this Lease shall terminate from the date of delivery
          of said written notice, and both parties hereto shall be released and
          discharged from all further obligations hereunder (except those
          obligations which expressly survive termination of the Lease term) and
          Tenant shall have a reasonable time thereafter to remove its property
          from the Premises. If Landlord terminates the Lease in accordance with
          this Section, Tenant shall pay the rent, properly apportioned up to
          date of such casualty. A total destruction of the Building shall
          automatically terminate this Lease.

          16.  Condemnation:
               ------------

               (a)  If the whole of the Premises or so much thereof as to render
          the balance unusable by Tenant for the proper conduct of its business
          shall be taken under power of eminent domain or transferred under
          threat thereof, then this Lease, at the option of either Landlord or
          Tenant exercised by either party giving notice to the other of such
          election within thirty (30) days after such conveyance or taking
          possession, whichever is earlier, shall forthwith cease and terminate
          and the rent shall be duly apportioned as of the date of such taking
          or conveyance. No award for any partial or entire taking shall be
          apportioned and Tenant hereby assigns to Landlord any award which may
          be made in such taking or condemnation, together with any and all
          rights of Tenant now or hereafter arising in or to the same or any
          part thereof. Notwithstanding the foregoing, Tenant shall be entitled
          to seek, directly from the condemning authority, an award for its
          removable trade fixtures, equipment and personal property and
          relocation expenses, if any, to the extent Landlord's award is not
          diminished. In the event of a partial taking which does not result in
          a termination of this Lease, Base Rent and Tenant's Pro Rata Share of
          the Operating Expense Differential shall be reduced in proportion to
          the reduction in the size of the Premises so taken and this Lease
          shall be modified accordingly. Promptly after obtaining knowledge
          thereof, Landlord or Tenant, as the case my be, shall notify the other
          of any pending or threatened condemnation or taking affecting the
          Premises or Building.

               (b)  If during the Term part of the Building is so taken or
          purchased as set out in Section 16(a), then:

                         (1)  If in the reasonable opinion of Landlord,
               substantial alteration or reconstruction of the Building is
               necessary or desirable as a result thereof, whether or not the
               Premises are or may be affected, Landlord shall have the right to
               terminate this Lease by giving the Tenant at least thirty (30)
               days' written notice of such termination; and

                         (2)  If more than one-third (1/3) of the number of
               square feet in the Premises is included in such taking or
               purchase and such reduction in square footage of the Premises
               renders the Premises unusable, in the reasonable estimation of
               Landlord and Tenant, for the permitted use hereunder as conducted
               by Tenant, Landlord and Tenant shall each have the right to
               terminate this Lease by giving the other at least thirty (30)
               days' written notice thereof.

                         (3)  If either party exercises its right to termination
               hereunder, this Lease shall terminate on the date stated in the
               notice; provided, however, that no termination pursuant to notice
               hereunder may occur later than sixty (60) days after the date of
               such taking.

                                      -17-
<PAGE>

          17.  Assignment and Subletting:
               -------------------------

               (a)  Tenant shall not voluntarily, by operation of law, or
          otherwise, assign, transfer, sublease or encumber this Lease or any
          interest herein or part with possession of all or any part of the
          Premises (any and all of which shall hereinafter be referred to as
          "Transfer") without Landlord's prior written consent, which consent
          shall not be unreasonably withheld. Landlord's consent to any Transfer
          and resulting subletting or assignment shall not relieve Tenant of its
          primary obligations hereunder, including the obligation for payment of
          all rents due hereunder. Any Transfer without the prior written
          consent of Landlord shall constitute a default hereunder and shall be
          void and shall confer no rights upon any third party, notwithstanding
          Landlord's acceptance of rent payments from any purported transferee.
          Landlord's consent shall not be considered unreasonably withheld if;
          among other things: (1) the proposed transferee's financial
          responsibility does not meet the same criteria Landlord uses to select
          other Building tenants; (2) the proposed transferee's business is not
          suitable for the Building considering the business of the other
          tenants and the Building's prestige or would result in a violation of
          an exclusive right granted to another tenant in the Building; (3) the
          proposed use is different than the permitted use; (4) the base rent
          and additional rent to be paid by the proposed transferee for the
          Premises is less than 85% of the current market rate for comparable
          premises in the Building; (5) if the Building is less than 90% leased
          at the time of the proposed Transfer and Landlord has comparably sized
          space available for lease in the Building; (6) the proposed transferee
          would impose additional obligations on Landlord or result in an
          excessive amount of foot traffic to and from the Premises or an
          excessive amount of people per square foot within the Premises; (7)
          Tenant is in default; or (8) any portion of the Building or Premises
          would become subject to additional or different governmental laws or
          regulations as a consequence of the proposed Transfer and/or the
          proposed transferee's use and occupancy of the Premises. Tenant
          acknowledges that the foregoing is not intended as an exhaustive list
          of the reasons for which Landlord may reasonably withhold its consent
          to a proposed Transfer.

               (b)  In the event of any Transfer of this Lease (or proposed
          Transfer, as the case may be) or all or any part of the Premises by
          Tenant, Landlord in addition to any rights contained herein, shall
          have the following options at its discretion; (1) to collect and
          receive 50% of the excess of rent and other cash consolidation due to
          Tenant from such sublessee or assignee over the Base Rent due
          hereunder; (2) to give Tenant written notice of Landlord's intention
          to terminate this Lease as to that part of the Premises which is the
          subject of the proposed Transfer, on the date such notice is given or
          on any later date specified therein, whereupon, on the date specified
          in such notice, Tenant's right to possession of the part of the
          Premises which is the subject of the proposed Transfer shall cease and
          this Lease shall thereupon be terminated, except as to any uncompleted
          obligations of Tenant; (3) to re-enter and take possession of the
          Premises or the part thereof subject to such Transfer, and to enforce
          all rights of Tenant, and receive and collect all rents and other
          payments due to Tenant, in accordance with such sublet or assignment
          of the Premises, or any part thereof, as if Landlord was the sublessor
          or assignor, and to do whatever Tenant is permitted to do pursuant to
          the terms of such sublease or assignment; or (4) Landlord, at its
          option and from time to time, may collect the rent from the subtenant
          or assignee, and apply the net amount collected to the rent herein
          reserved. Notwithstanding the foregoing, Tenant may, at any time
          within five (5) business days after the Landlord exercises any of its
          rights pursuant to this subparagraph 17(b), retract its request to
          Transfer by giving written notice to Landlord to that effect, in which
          case the Transfer and the Landlord's exercise of its rights pursuant
          to subparagraph 17(b) shall be of no further force or effect.

               (c)  The sale of all or a majority of the stock of Tenant to one
          investor or a related group of investors, if Tenant is a corporation,
          or the sale of all or a majority of the ownership interest in Tenant,
          if Tenant is a partnership, or a limited liability entity, or the sale
          of all or substantially all of the assets of Tenant shall constitute a
          Transfer for purpose of this Lease. Notwithstanding the foregoing
          sentence Tenant may assign its entire interest under this Lease or
          sublet the Premises to a wholly-owned corporation, partnership, or
          other legal entity or controlled subsidiary or parent of Tenant or to
          any successor to Tenant by purchase including, without limitation, the
          purchase of the stock of Tenant, merger, consolidation or
          reorganization (hereinafter collectively referred to as "Permitted
          Transfer") without the consent of Landlord, provided: (i) Tenant is
          not in default under this Lease; (ii) if such proposed transferee

                                      -18-
<PAGE>

          is a successor to Tenant by purchase, merger, consolidation or
          reorganization, the continuing or surviving entity shall own
          substantially all of the asset of Tenant and the net worth of the
          surviving entity exclusive of good will shall equal or exceed the net
          worth of the Tenant exclusive of goodwill at the date of the execution
          of this Lease, and (iii) in no event shall any Transfer release or
          relieve Tenant from any of its obligations under this Lease.

               (d)  At the time of making a request for Landlord's consent to a
          Transfer and not less than fifteen (15) days prior to the proposed
          effective date thereof, Tenant shall provide to Landlord such
          information as Landlord, its accountants and attorneys, shall
          reasonably require with respect to such proposed Transfer, including
          but not limited to name and address of the proposed transferee,
          description of business operations, financial information, rental rate
          and material terms of the proposed Transfer and certificate of
          corporate authority and good standing or partnership certificate, or
          similar certificate for a limited liability entity, as applicable.
          Tenant shall reimburse Landlord for its reasonable attorneys' and
          accountants' fees incurred in the review of any proposed Transfer.

               (e)  Consent of Landlord to a Transfer shall not relieve Tenant
          from seeking consent to any subsequent Transfers.

               (f)  Subletting or assignments by subtenants or assignees shall
          not be permitted under any circumstances, nor shall Tenant be
          permitted to further assign this Lease or sublet all or any part of
          the Premises during any period of time that all or any portion of the
          Base Rent is abated or in default. Except for a Transfer referred to
          in subparagraph 17(c), no option to renew or extend the term of this
          Lease or to lease additional space, if any, shall be exercisable by
          any subtenant or assignee.

               (g)  All subleases or assignments shall be in writing and a copy
          thereof provided to Landlord within ten (10) days of its effective
          date. All subleases shall further contain an express provision that in
          the event of any default by Tenant under this Lease and upon notice
          thereof to the subtenant from Landlord, all rentals payable by the
          subtenant shall be paid directly to Landlord, for the Tenant's
          account, until subsequent notice from Landlord that such default has
          been cured. Notwithstanding the foregoing, receipt by Landlord of rent
          directly from the subtenant shall not be considered a waiver of the
          default on the part of Tenant, nor an acceptance of such subtenant.

               (h)  No sublease or assignment shall be effective until approved
          in writing by Landlord.

               (i)  Tenant shall pay to Landlord a non-refundable processing fee
          in the amount of five hundred and no/l00 dollars ($500.00) plus
          reasonable attorney's fees for preparation and review of the
          documentation in connection with each proposed Transfer.

          18.  Estoppel Certificate: Tenant further agrees at any time and from
time to time on or before fifteen (15) days after written request by Landlord,
to execute, acknowledge and deliver to Landlord an estoppel certificate
certifying (to the extent it believes the same to be true) 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), that there have been no defaults thereunder by Landlord or
Tenant (or if there have been defaults, setting forth the nature thereof), the
date to which the rent and other charges have been paid, if any, Tenant claims
no present charge, lien, claim or offset against rent (or specifying the nature
of any such claims), and such other matters as may be reasonably required by
Landlord, Landlord's mortgagee, or any potential purchaser of the Building, it
being intended that any such statement delivered pursuant to this Paragraph may
be relied upon by any prospective purchaser of all or any portion of Landlord's
interest herein, or a holder of any mortgage or deed of trust encumbering any
portion of the Building Complex. Tenant's failure to deliver such statement
within such time shall be a default under this Lease. Notwithstanding the
foregoing, in the event that Tenant does not execute the statement required by
this paragraph, Tenant hereby grants to Landlord a power of attorney coupled
with an interest to act as Tenant's attorney in fact for the purpose of
executing such statement or statements required by this Paragraph.

                                      -19-
<PAGE>

               (a)  The following events (herein referred to as an "event of
          default") shall constitute a default by Tenant hereunder;

                    (1)  Tenant shall fail to pay when due any installment of
               Base Rent, Additional Rent or any other amounts payable
               hereunder; provided that Tenant shall be entitled to one (1) five
               (5) day grace period during every calendar year during which
               period if the Tenant pays the amounts due it shall not be in
               default and no late charges shall be assessed.

                    (2)  Tenant shall fail to perform any of the other non-
               monetary agreements, terms, covenants or conditions hereof on
               Tenant's part to be performed, and such nonperformance shall
               continue for a period of fifteen (15) days after notice thereof
               by Landlord to Tenant; provided, however, that if Tenant cannot
               reasonably cure such nonperformance within fifteen (15) days,
               Tenant shall not be in default if it commences cure within said
               fifteen (15) days and diligently and continuously pursues the
               same to completion, with completion occurring in all instances
               within seventy-five (75) days;

                    (3)  This Lease or the estate of Tenant hereunder shall be
               transferred to or shall pass to or devolve upon any other person
               or party in violation of the provisions of this Lease;

                    (4)  This Lease or the Premises or any part thereof shall be
               taken upon execution or by other process of law directed against
               Tenant, or shall be taken upon or subject to any attachment at
               the instance of any creditor or claimant against Tenant, and said
               attachment shall not be discharged or disposed of within fifteen
               (15) days after the levy thereof;

                    (5)  Tenant shall file a petition in bankruptcy or
               insolvency or for reorganization or arrangement under the
               bankruptcy laws of he United States or under any insolvency act
               of any state, or shall voluntarily take advantage of any such law
               or act by answer or otherwise, or shall be dissolved or shall
               make an assignment for the benefit of creditors;

                    (6)  Involuntary proceeding under any such bankruptcy law or
               insolvency act or for the dissolution of Tenant shall be
               instituted against Tenant, or a receiver or trustee shall be
               appointed of all or substantially all of the property of Tenant,
               and such proceedings shall not be dismissed or such receivership
               or trusteeship vacated within sixty (60) days after such
               institution or appointment;

                    (7)  Tenant shall fail to take possession of the Premises
               within thirty (30) days of the Commencement Date;

                    (8)  Tenant shall abandon or permanently vacate the Premises
               for ten (10) consecutive days;

                    (9)  Tenant shall fail to obtain a release of any mechanic's
               lien or post a bond, as required herein within twenty (20) days
               after notice of the filing of the notice of intent to lien;

                    (10) A guarantor of this Lease, if any, or a general partner
               of Tenant (if Tenant is a general or limited partnership),
               becomes a debtor under any state or federal bankruptcy
               proceedings, or becomes subject to receivership or trusteeship
               proceedings, whether voluntary or involuntary; except in the case
               of a guarantor, Tenant shall not be in default if a substitute
               guarantor, with acceptable creditworthiness and financial
               abilities in light of the responsibilities of Tenant hereunder,
               and otherwise acceptable to Landlord, is provided to Landlord
               within fifteen (15) days; and

                                      -20-
<PAGE>

                    (11) All or any part of the personal property of Tenant is
               seized, subject to levy or attachment, or similarly repossessed
               or removed from the Premises, or a receiver is appointed for all
               or substantially all of Tenant's assets.

               (b)  Upon the occurrence of an event of default, Landlord shall
          have the right, at its election, then or at any time thereafter and
          while any such event of default shall continue, to pursue any one or
          more of the following remedies without notice or demand whatsoever:

                    (1)  Except as otherwise provided in C.R.S. ss. 13-40-
               104(l)(e) and (e.5), as amended, give Tenant written notice of
               Landlord's intent to terminate this Lease on the date of such
               notice or on any later date as may be specified herein, whereupon
               Tenant's right to possession of the Premises shall cease and this
               Lease, except as to Tenant's liability, shall be terminated.

                    In the event this Lease is terminated in accordance with the
               provisions of this Paragraph, Tenant shall remain liable to
               Landlord for damages in an amount equal to the Base Rent,
               Additional Rent and other sums which would have been owing by
               Tenant hereunder for the balance of the Term had this Lease not
               been terminated, less the net proceeds, if any, of any reletting
               of the Premises by Landlord subsequent to such termination,
               deducting from such proceeds all Landlord's expenses including,
               without limitations, all repossession costs, brokerage
               commissions, legal expenses, attorneys' fees, expenses of
               employees, alteration and repair costs and expenses of
               preparation for such reletting. Landlord shall be entitled to
               collect such damages from Tenant monthly on the days on which the
               Base Rent and other charges would have been payable hereunder if
               this Lease had not been terminated. Alternatively, at the option
               of the Landlord, in the event this Lease is so terminated,
               Landlord shall be entitled to recover forthwith against Tenant as
               damages for loss of the bargain and not as a penalty an aggregate
               sum, which at the time of such termination of this Lease,
               represents the excess, if any, of the aggregate of the Base Rent,
               Additional Rent and all other charges payable by Tenant hereunder
               that would have accrued for the balance of the Term over the
               aggregate fair market rental value of the Premises (such rental
               value to be computed on the basis of Tenant paying not only a
               Base Rent and Additional Rent to Landlord for the use and
               occupation of the Premises, but also such other charges as are
               required to be paid by Tenant under the terms of this Lease) for
               the balance of such Term, both discounted to present worth at the
               rate of four percent (4%) per annum.

                    (2) Reenter and take possession of the Premises or
               any part thereof, and repossess the same as of Landlord's former
               estate and expel Tenant and those claiming through and under
               Tenant, and remove the effects of both or either, using such
               force for such purposes as may be necessary, without being liable
               for prosecution thereof, without being deemed guilty of any
               manner of trespass, and without prejudice to any remedies for
               arrears of Base Rent, Additional Rent and other charges payable
               or preceding breach of covenants or conditions. Should Landlord
               elect to reenter as provided in this subparagraph, or should
               Landlord take possession pursuant to legal proceedings or
               pursuant to any notice provided for by law, Landlord from time to
               time, without terminating this Lease, relet the Premises or any
               part thereof in Landlord's or Tenant's name, but for the account
               of Tenant, for such term or terms (which may be greater or less
               than the period which would otherwise have constituted the
               balance of the Term of this Lease) and on such conditions and
               upon other terms (which may include concessions of free Base Rent
               and alteration and repair of the Premises) as Landlord, in its
               sole discretion, may determine, and Landlord may collect and
               receive the Base Rents therefor. Landlord shall in no way be
               responsible or liable for any failure to relet the Premises, or
               any part thereof, or for any failure to collect any Base Rent due
               upon such reletting. No such reentry or taking possession of the
               Premises by Landlord shall be construed as an election on
               Landlord's part to terminate this Lease unless a written notice
               of such intention is given to Tenant. No notice from Landlord
               hereunder or under a forcible entry and detainer statute or
               similar law shall constitute an election by Landlord to terminate
               this Lease unless such notice specifically so states. Landlord
               reserves the right following any such reentry

                                      -21-
<PAGE>

               and/or reletting to exercise its right to terminate this Lease by
               giving Tenant such written notice, in which event the Lease will
               terminate as specified in said notice.

                    In the event that Landlord does not elect to terminate this
               Lease but takes possession as provided for in this subparagraph,
               Tenant shall pay to Landlord (i) the Base Rent, Additional Rent
               and other charges as herein provided which would be payable
               hereunder if such repossession had not occurred, less (ii) the
               net proceeds, if any, of any reletting of the Premises after
               deducting all Landlord's reasonable expenses including, without
               limitation, all repossession costs, brokerage commissions, legal
               expenses, attorneys' fees, expenses of employees, alteration and
               repair costs and expense of preparation for such reletting.
               Tenant shall pay such Base Rent, Additional Rent and other sums
               to Landlord monthly on the days on which the Base Rent would have
               been payable hereunder if possession had not been retaken.

               (c)  No failure by Landlord to insist upon the strict performance
          of any agreement, term, covenant or condition hereof or to exercise
          any right or remedy consequent upon a breach thereof, and no
          acceptance of full or partial rent during the continuance of any such
          breach, shall constitute a waiver of any such breach of such
          agreement, term, covenant or condition. No agreement, term, covenant
          or condition hereof to be performed or complied with by either
          Landlord or Tenant, and no breach thereof, shall be waived, altered or
          modified except by written instrument executed by the other party. No
          waiver of any breach shall affect or alter this Lease, but each and
          every agreement, term, covenant and condition hereof shall continue in
          full force and effect with respect to any other then existing or
          subsequent breach thereof. Notwithstanding any unilateral termination
          of this Lease, this Lease shall continue in force and effect as to any
          provisions hereof which require observance or performance of Landlord
          or Tenant subsequent to termination.

               (d)  Any rents or other amounts owing to Landlord hereunder which
          are not paid within ten (10) days of the date they are due, shall
          thereafter bear interest from the due date at the rate of four percent
          (4%) over the prime rate of interest charged by Wells Fargo Bank of
          Denver (or its successor) ("Interest Rate") until paid. Similarly, any
          amounts paid by Landlord to cure any default of Tenant or to perform
          any obligation of Tenant, shall, if not repaid by the Tenant within
          five (5) days of demand by Landlord, thereafter bear interest from the
          date paid by Landlord at the Interest Rate until paid. In addition to
          the foregoing, Tenant shall pay to Landlord whenever any Base Rent,
          Additional Rent or any other sums due hereunder remain unpaid more
          than ten (10) days after the due date thereof, a late charge equal to
          ten percent (10%) of the amount due. Further, in the event of default
          by Tenant, in addition to all other rights and remedies, Landlord
          shall be entitled to receive from Tenant all sums, the payment of
          which may previously have been waived or abated by Landlord, or which
          may have been paid by Landlord pursuant to any agreement to grant
          Tenant a rental abatement or other monetary inducement or concession,
          including but not limited to any tenant finish allowance, moving
          allowance, and leasing commissions, together with interest thereon
          from the date or dates such amounts were paid by Landlord or would
          have been due from Tenant but for the abatement, at the Interest Rate,
          until paid; provided, that Landlord may only recover for such amounts
          to the extent they have not otherwise been amortized over the Term of
          the Lease prior to the default or as part of any future Base Rent
          awarded to Landlord. It is understood and agreed that such concession
          or abatement was made on the condition and basis that Tenant fully
          perform all obligations and covenants under the Lease for the entire
          term.

               (e)  Each right and remedy provided for in this Lease shall be
          cumulative and shall be in addition to every other right or remedy
          provided for in this Lease now or hereafter existing at law or in
          equity or by statute or otherwise, including, but not limited to,
          suits for injunctive or declaratory relief and specific performance.
          The exercise or commencement of the exercise by Landlord of any one or
          more of the rights or remedies provided for in this Lease now or
          hereafter existing at law or in equity or by statute or otherwise
          shall not preclude the simultaneous or subsequent exercise by Landlord
          of any or all other rights or remedies provided for in this Lease, or
          now or hereafter existing at law or in equity or by statue or
          otherwise. All costs incurred by Landlord in connection with
          collecting any amounts and damages owing by Tenant pursuant to the
          provisions of this Lease or to enforce any provision of this Lease,
          including by

                                      -22-
<PAGE>

          way of example, but not limitation, reasonable attorneys' fees from
          the date any such matter is turned over to an attorney, shall also be
          recoverable by Landlord from Tenant. Landlord and Tenant agree that
          any action or proceeding arising out of this Lease shall be heard by a
          court sitting without a jury and thus hereby waive all rights to a
          trial by jury.

               (f)  The Tenant and Landlord each hereby expressly, irrevocably,
          fully and forever release, waive and relinquish any and all right to
          trial by jury and all right to receive punitive, exemplary and
          consequential damages from the other (or any past, present or future
          director, officer, member, partner, employee, agent, representative,
          or advisor of the other) in any claim, demand, action, suit,
          proceeding or cause of action in which the Tenant and Landlord are
          parties, which in any way (directly or indirectly) arises out of,
          results from, or relates to, any of the following, in each case
          whether now existing or hereafter arising and whether based on
          contract or tort or any other legal basis: this Lease; any past,
          present or future act, omission, conduct or activity with respect to
          this Lease; any transactions, event or occurrence contemplated by this
          Lease; the performance of any obligation or the exercise of any right
          under this Lease; or the enforcement of this Lease. The Tenant and
          Landlord each agree that this Agreement constitutes written consent
          that trial by jury shall be waived in any such claim, demand, action,
          suit, proceeding or other cause of action and agree that the Tenant
          and Landlord each shall have the right at any time to file this Lease
          with the clerk or judge of any court in which any such claim, demand,
          action, suit, proceeding or other cause of action may be pending as
          written consent to waiver of trial by jury.

                                             /s/                 /s/
                                             ----------------    ---------------
                                             Landlord            Tenant

          20.  Landlord's Lien:  Intentionally Deleted
               ---------------

          21.  Uniform Commercial Code:  Intentionally Deleted
               -----------------------

          22.  Removal of Tenant's Property: All movable furniture and personal
               ----------------------------
effects of Tenant not removed from the Premises upon the vacation or abandonment
thereof or upon the termination of this Lease for any cause whatsoever shall
conclusively be deemed to have been abandoned and may be appropriated, sold,
stored, destroyed or otherwise disposed of by Landlord without notice to Tenant
and without obligation to account therefor, and Tenant shall reimburse Landlord
for all expenses incurred in connection with the disposition of such property.

          23.  Holdover: Should Tenant, without Landlord's consent, holdover
               --------
after the termination of this Lease and continue to pay rent, Tenant shall
become a tenant from month to month only upon each and all of the terms herein
provided as may be applicable to such month to month tenancy and any such
holdover shall not constitute an extension of this Lease. During such holdover,
without Landlord's consent, Tenant shall pay monthly Base Rent equal to two
hundred percent (200%) of the Base Rent and Additional Rent due for the last
month of the Term of the Lease, plus the other monetary charges as provided
herein. In the event of Tenant holdover after the termination of this Lease with
Landlord's consent all other terms of this Paragraph 23 shall apply, however,
Tenant shall pay Landlord monthly Base Rent in the amount agreed upon by
Landlord and Tenant or, in the absence of an agreement an amount equal to one
hundred fifty percent (150%) of the Base Rent and Additional Rent due for the
last month of the Term of the Lease. Such tenancy (whether with or without
Landlord's consent) shall continue until terminated by Landlord, as provided by
law, or until Tenant shall have given to Landlord at least thirty (30) days
written notice prior to the last day of the calendar month intended as the date
of termination of such month to month tenancy.

          24.  Common Areas: Except as otherwise specifically provided herein,
               ------------
all access roads, courtyards, and other areas, facilities or improvements
furnished by Landlord are for the general and nonexclusive use in common of all
tenants of the Building, and those persons invited upon the land upon which the
Building is situated and shall be subject to the exclusive control and
management of Landlord, and Landlord shall have the right, without obligation to
establish, modify and enforce such rules and regulations, which the Landlord may
deem reasonable and/or necessary.

                                      -23-
<PAGE>

          25.  Surrender and Notice: Upon the expiration or earlier termination
               --------------------
of this Lease, Tenant shall promptly 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 all of its movable
furniture and other effects and such alterations, additions and improvements as
Landlord shall require Tenant to remove pursuant to Paragraph 10 hereof. In the
event Tenant fails to so vacate the Premises on a timely basis as required,
Tenant shall be responsible to Landlord for all costs and damages, including but
not limited to any amounts required to be paid to third parties who were to have
occupied the Premises, incurred by Landlord as a result of such failure, plus
interest thereon at the Interest Rate on all amounts not paid by Tenant within
five (5) days of demand, until paid in full.

          26.  Sales; Conveyance and Assignment: Nothing in this Lease shall
               --------------------------------
restrict the right of Landlord to sell, convey, assign or otherwise deal with
its interest in the Building subject only to the rights of Tenant under this
Lease. In the event Landlord conveys its interest in the Building to an
affiliate of Landlord, Tenant shall, if requested by Landlord, execute an
Estoppel Certificate for the benefit of the new owner.

          27.  Subordination; Non-Disturbance and Attornment:
               ---------------------------------------------

               (a)  This Lease is and shall be subject and subordinate in all
          respects to any and all mortgages and deeds of trust now or hereafter
          placed on the Building, the Building Complex or the land on which it
          is situated, and to all renewals, modifications, consolidations,
          replacements and extensions thereof.

               (b)  Subject to subparagraph (c) and receipt from the Landlord's
          mortgagee of the non- disturbance agreement provided for in
          subparagraph 27(f), if the interest of Landlord is transferred to any
          person (herein called ("Purchaser") by reason of foreclosure or other
          proceedings for enforcement of any mortgage or deed of trust, or by
          delivery of a deed in lieu of such foreclosure or other proceedings,
          Tenant shall immediately and automatically attorn to Purchaser.

               (c)  No attornment by Tenant to the holder of any mortgage or
          deed of trust which would be subordinate to this Lease but for the
          provisions of subparagraph (a) shall be effective unless Purchaser
          delivers to Tenant written undertaking that this Lease and Tenant's
          rights hereunder shall continue undisturbed while Tenant is not in
          default, despite such enforcement proceedings and transfer.

               (d)  Upon attornment under subparagraph (b), this Lease shall
          continue in full force and effect as a direct Lease between Purchaser
          and Tenant, upon all of the same terms, conditions and covenants as
          are set forth in this Lease except that, after such attornment,
          Purchaser shall not be liable for any act of omission of any previous
          Landlord.

               (e)  The subordination and attornment provisions of this
          Paragraph 27 shall be self-operating and except as set out in
          subparagraph (c), no further instrument shall be required.
          Nevertheless Tenant, on request by and without cost to Landlord or any
          successor in interest, shall execute and deliver any and all
          reasonable instruments further evidencing such subordination and
          (where applicable hereunder) attornment. Tenant hereby irrevocably
          appoints Landlord as attorney-in-fact of Tenant to execute, delivery
          and record any such documents and instruments in the name and on
          behalf of Tenant if Tenant fails to do so.

               (f)  Landlord agrees that substantially concurrent with the
          execution of this Lease by both Landlord and Tenant, that it will
          deliver to Tenant a non-disturbance agreement from Landlord's
          mortgagee, which non- disturbance agreement shall be on the
          mortgagee's standard form.

          28.  Payments After Termination: No payments of money by Tenant to
               --------------------------
Landlord after the termination of this Lease, in any manner, or after giving of
any notice (other than a demand for payment of money) by Landlord to Tenant,
shall reinstate, continue or extend the term of this Lease or affect any notice
given to Tenant prior to the payment of such money, it being agreed that after
the service of notice of the commencement of a suit or other final judgement
granting Landlord possession of the Premises, Landlord may receive and collect
any sums of rent due, or any other sums of money due under the terms of this
Lease or otherwise exercise its rights and remedies hereunder.

                                      -24-
<PAGE>

The payment of such sums of money, whether as rent or otherwise, shall not waive
said notice or in any manner affect any pending suit or judgement theretofore
obtained.

          29.  Authorities for Action and Notice:
               ---------------------------------

          (a)  Except as otherwise provided herein, Landlord may, for any matter
pertaining to this Lease, act by and through its building manager or any other
person designated in writing from time to time.

          (b)  All notices or demands required or permitted to be given
hereunder shall be in writing, and shall be deemed duly served when received, if
hand delivered or delivered by facsimile transmission or overnight courier, or
three (3) days after deposited in the United States mail, with proper postage
prepaid, certified or registered, return receipt requested, addressed to:

               Landlord:      Centennial Venture I, LLC
                              Attn:  Randy Nichols
                              1200 17th Street, Suite 890
                              Denver, Colorado 80202

               cc:            Jones Lang, LaSalle, Inc.
                              Attn:  Linda Kaboth
                              950 Seventeenth Street, Suite 2000
                              Denver, Colorado

               Tenant:   Prior to the Commencement Dat

                              Webb Interactive Services, Inc.
                              1800 Glenarm, Suite 600
                              Denver, Colorado 80202

                         After the Commencement Date

                              Webb Interactive Services, Inc.
                              1899 Wynkoop, Suite 600
                              Denver, Colorado 80202

          Either party shall have the right to designate in writing, served as
above provided, a different address to which notice is to be provided. The
foregoing shall in no event prohibit notice from being given as provided in Rule
4 of the Colorado Rules of Civil Procedure, as the same may be amended from time
to time.

          30.  Liability of Landlord: Landlord's liability under this Lease
shall be limited to Landlord's estate and interest in the Building (or to the
proceeds thereof) and no other property or other assets of Landlord shall be
subject to levy, execution or other enforcement procedure for the satisfaction
of Tenant's remedies under or with respect to this Lease, the relationship of
Landlord and Tenant hereunder or Tenant's use and occupancy of the Premises.
Nothing contained in this Paragraph shall be construed to permit Tenant to
offset against rents due a successor landlord, a judgement (or other judicial
process) requiring the payment of money by reason of any default of a prior
landlord, except as otherwise specifically set forth herein.

          31.  Brokerage: Landlord and Tenant each represents and warrants that
               ---------
it has dealt only with Fuller and Company as agent for Tenant ("Tenant's
Broker") and Cushman Realty Corporation as agent for Landlord (the "Landlord's
Broker") in the negotiation of this Lease. Landlord shall make payment of the
brokerage fee due to Landlord's Broker pursuant and in accordance with
Landlord's separate agreement with Landlord's Broker. Landlord's Broker shall
pay Tenant's Broker pursuant to and in accordance with a separate coop agreement
with Tenant's Broker. Landlord and Tenant hereby agree to indemnify, defend and
hold the other harmless of and from any and all loss, costs, damages or expenses
(including, without limitation, all attorneys' fees and disbursements) by

                                      -25-
<PAGE>

reason of any claim of or liability to any other broker or person claiming
through Landlord and Tenant, respectively, and arising out of or in connection
with the negotiation, execution and delivery of this Lease. Additionally, Tenant
acknowledges and agrees that Landlord shall have no obligation for payment of
any brokerage fee or similar compensation to any person with whom Tenant has
dealt or may in the future deal with respect to leasing of any additional or
expansion space in the Building or renewals or extensions of this Lease. Tenant
further acknowledges that Landlord's Broker is the exclusive broker for the
Landlord and that it has no fiduciary duties to Tenant.

          32.  Tenant's Taxes:
               --------------

               (a)  Tenant shall be liable for and shall pay at least ten (10)
          days before delinquency and Tenant hereby agrees to indemnify and hold
          Landlord harmless from and against any liability in connection with,
          all taxes levied against any personal property, fixtures, machinery,
          equipment, apparatus, systems and appurtenances placed by or on behalf
          of Tenant in or about or utilized by Tenant in, upon or in connection
          with the Premises ("Equipment Taxes"). If any Equipment Taxes are
          levied against Landlord or Landlord's property or if the assessed
          value of Landlord's property is increased by the inclusion therein of
          a value placed upon such personal property, fixtures, machinery,
          equipment, apparatus, systems or appurtenances of Tenant, and if
          Landlord, after written notice to Tenant, pays the Equipment Taxes or
          taxes based upon such an increased assessment (which Landlord shall
          have the right to do regardless of the validity of such levy, but
          under proper protest if requested by Tenant prior to such payment and
          if payment under protest is permissible), Tenant shall pay to Landlord
          upon demand, as Additional Rent hereunder, the taxes so levied against
          Landlord or the proportion of such taxes resulting from such increase
          in the assessment; provided, however, that in any such event, Tenant
          shall have the right, on behalf of Landlord and with Landlord's full
          cooperation, but at no cost to Landlord, to bring suit in any court of
          competent jurisdiction to recover the amount of any such tax so paid
          under protest, and any amount so recovered shall belong to Tenant
          (provided Tenant has previously paid such amount to Landlord).
          Notwithstanding the foregoing to the contrary, Tenant shall cooperate
          with Landlord to the extent reasonable necessary to cause the
          fixtures, furnishings, equipment and other personal property to be
          assessed and billed separately from the real property of which the
          Premises form a part, and Landlord shall use reasonable efforts to
          treat all other Tenants on the same basis.

               (b)  Tenant shall pay to Landlord, as Additional Rent, any
          excise, sales, privilege, gross receipts or other tax, assessment or
          other charge (other than income or franchise taxes) imposed, assessed
          or levied by any governmental or quasi-governmental authority or
          agency upon Landlord on account of this Lease, the rent or other
          payments made by Tenant hereunder, any other benefit received by
          Landlord hereunder, Landlord's business as a lessor hereunder, or
          other in respect of or as a result of the agreement or relationship of
          Landlord and Tenant hereunder.

          33.  Substitution of Premises: Prior to the commencement of
               ------------------------
construction of the Leasehold Improvements on the sixth (//6//th) floor,
Landlord shall have the right to relocate the Premises to either Floor 5 or 7 in
accordance with the following: (a) the new Premises shall be substantially the
same in size, dimensions, configuration, decor, and nature as are the Premises
described in this Lease, and shall be placed in substantially that condition by
Landlord at its cost; (b) the physical relocation of the Premises shall be
accomplished by Landlord at its cost; (c) Landlord shall give Tenant written
notice of landlord's intention to relocate the Premises; (d) all reasonable
costs incurred by Tenant as a result of the relocation, including, without
limitation, costs incurred in changing addresses on stationery, business cards,
directories, advertising, and other reasonable items, shall be paid by Landlord;
(e) if the relocated Premises are smaller than the Premises as they existed
before the relocation, Annual Base Rent shall be reduced pro-rata; and, (f) the
parties hereto shall immediately execute an amendment to this Lease stating the
relocation of the Premises and the reduction of rent, if any. Once the Leasehold
Improvements on Floor 6 have been commenced, this Paragraph 33 shall be null and
void.

          34.  Rights Reserved to Landlord:
               ---------------------------

               (a)  All portions of the Building are reserved to Landlord except
          the Premises and the inside surfaces of all walls, windows and doors
          bounding in the Premises, but including exterior building walls,

                                      -26-
<PAGE>

          core corridor walls and doors and any core corridor entrance. Landlord
          also reserves any space in or adjacent to the Premises used for
          shafts, stacks, pipes, conduits, fan rooms, ducts, electric or other
          utilities, sinks or other building facilities, and the use thereof, as
          well as the right to access thereto through the Premises for the
          purposes of operation, maintenance and repair, upon reasonable notice,
          except in the event of emergencies or apparent emergencies, when no
          prior notice shall be required.

               (b)  Landlord shall have the following rights without liability
          to Tenant for damage or injury to property, person or business (all
          claims for damage being hereby waived and released), and without
          effecting an eviction or disturbance of Tenant's use or possession of
          the Premises or giving rise to any claim for setoffs or abatement of
          rent:

                    (1)  To enter the Premises as more fully provided in this
               Lease.

                    (2)  To install and maintain signs on the exterior and
               interior of the Building, except within the Premises, provided
               the signs do not block either completely or partially the
               exterior windows of the Premises.

                    (3)  To have pass keys to the Premises.

                    (4)  To decorate, remodel, repair, alter or otherwise
               prepare the Premises for reoccupancy during the last sixty (60)
               days of the term hereof if, during or prior to such time, Tenant
               has vacated the Premises, or at any time after Tenant abandons
               the Premises.

          35.  Force Majeure Clause: Except as provided in subparagraphs 2(c)(6)
               ---------------------
and 7(e), wherever there is provided in this Lease a time limitation for
performance by Landlord of any obligation, including but not limited to
obligations related to construction, repair, maintenance or service, the time
provided for shall be extended for as long as and to the extent that delay in
compliance with such limitation is due to an act of God, governmental control or
other factors beyond the reasonable control of Landlord.

          36.  Signage:
               -------

               (a)  No sign, advertisement or notice shall be inscribed, painted
          or affixed on any part of the inside or outside of the Building unless
          of such color, size and style and in such place upon or in the
          Building as shall be first designated by Landlord, but there shall be
          no obligation or duty on Landlord to allow any sign, advertisement or
          notice to be inscribed, painted or affixed on any part of the inside
          or outside of the Building. A directory in a conspicuous place, with
          the names of Tenant, not to exceed one (1) name per every 2000
          rentable square feet of the Premises, shall be provided by Landlord on
          a one time basis. Any necessary revision to such directory shall be
          made by Landlord, at Tenant's expense, within a reasonable time after
          written notice from Tenant of the change making the revision
          necessary. Landlord shall have the right to remove all nonpermitted
          signs without notice to Tenant and at the expense of Tenant.

               (b)  Tenant shall only be permitted to install building standard
          signs and logos, subject to Landlord's prior written consent and
          criteria as to size, design, materials and location.

          37.  Attorneys' Fees:  In the event of any dispute hereunder, or any
               ---------------
default in the performance of any term or condition of this Lease, the
prevailing party shall be entitled to recover all costs and expenses associated
therewith, including reasonable attorneys' fees.

          38.  Miscellaneous:
               -------------

               (a)  The rules and regulations attached hereto as Exhibit E, as
          well as such rules and regulations as may hereafter be adopted by
          Landlord for the safety, care and cleanliness of the Premises and the
          Building and the preservation of good order thereon, are hereby
          expressly made a part hereof, and Tenant agrees to obey all such rules
          and regulations. The violation of any of such rules and regulations by
          Tenant

                                      -27-
<PAGE>

          shall be deemed a breach of this Lease by Tenant affording Landlord
          all the remedies set forth herein. Landlord shall not be responsible
          to Tenant for the nonperformance by any other tenant or occupant of
          the Building of any of said rules and regulations. Landlord reserves
          the right from time to time to amend and modify the rules and
          regulations. Such amendments or modifications shall be effective upon
          delivery to Tenant.

               (b)  The term "Landlord" as used in this Lease, so far as
          covenants or obligations on the part of Landlord are concerned, shall
          be limited to mean and include only the owner or owners of the
          Building at the time in question, and in the event of any transfer or
          transfers of the title thereto. Except for the Landlord's obligation
          to construct and deliver the Base Building and the Leasehold
          Improvements and the warranty associated with the Leasehold
          Improvements, Landlord herein named (and in the case of any subsequent
          transfers or conveyances, the then grantor) shall be automatically
          released from and after the date of such transfer or conveyance of all
          liability in respect to the performance of any covenants or
          obligations on the part of Landlord contained in this Lease thereafter
          to be performed and relating to events occurring thereafter; provided
          that any funds in the hands of Landlord or the then grantor at the
          time of such transfer in which Tenant has an interest shall be turned
          over to the grantee, and any amount then due and payable to Tenant by
          Landlord or the then grantor under any provisions of this Lease shall
          be paid to Tenant.

               (c)  This Lease shall be construed as though the covenants herein
          between Landlord and Tenant are independent and not dependent and
          Tenant shall not be entitled to any setoff of the rent or other
          amounts owing hereunder against Landlord, if Landlord fails to perform
          its obligations set forth herein, except as herein specifically set
          forth; provided, however, the foregoing shall in no way impair the
          right of Tenant to commence a separate action against Landlord for any
          violation by Landlord of the provisions hereof so long as notice is
          first given to Landlord and any holder of a mortgage or deed of trust
          covering the Building Complex or any portion thereof whose address
          Tenant has been notified in writing and so long as an opportunity has
          been granted to Landlord and such holder to correct such violation as
          provided in subparagraph (g) hereof.

               (d)  If any clause or provision of this Lease is illegal, invalid
          or unenforceable under present or future laws effective during the
          term of this Lease, then and in that event, it is the intention of the
          parties hereto that the remainder of this Lease shall not be affected
          thereby, and it is also the intention of the parties to this Lease
          that in lieu of each clause or provision of this Lease that is
          illegal, invalid or unenforceable, there shall be added as a part of
          this Lease a clause or provision as similar in terms to such illegal,
          invalid or unenforceable clause or provision as may be possible and be
          legal, valid and enforceable, provided such addition does not increase
          or decrease the obligations of or derogate from the rights or powers
          of either Landlord or Tenant.

               (e)  The captions of each paragraph are added as a matter of
          convenience only and shall be considered of no effect in the
          construction of any provision or provisions of this Lease.

               (f)  Except as herein specifically set forth, all terms,
          conditions and covenants to be observed and performed by the parties
          hereto shall be applicable to and binding upon their respective heirs,
          administrators, executors, successors and assigns. The terms,
          conditions and covenants hereof shall also be considered to be
          covenants running with the land.

               (g)  Except as otherwise specifically provided herein, in the
          event Landlord shall fail to perform any of the agreements, terms,
          covenants or conditions hereof on Landlord's part to be performed, and
          such nonperformance shall continue for a period of thirty (30) days
          after written notice thereof, from Tenant to Landlord, or if such
          performance cannot be reasonably had within such thirty (30) day
          period, and Landlord shall not in good faith have commenced such
          performance within such thirty (30) day period and proceed therewith
          to completion, it shall be considered a default of Landlord under this
          Lease. Tenant shall give written notice to Landlord in the matter
          herein set forth and shall afford Landlord a reasonable opportunity to
          cure any such default. In addition, Tenant shall send notice of such
          default by certified or

                                      -28-
<PAGE>

          registered mail, with proper postage prepaid, to the holder of any
          mortgages or deeds of trust covering the Building Complex or any
          portion thereof of whose address Tenant has been notified in writing
          and shall afford such holder a reasonable opportunity to cure any
          alleged default on Landlord's behalf.

               (h)  If there is more than one entity or person which or who are
          the Tenants under this Lease, the obligations imposed upon Tenant
          under this Lease shall be joint and several.

               (i)  No act or thing done by Landlord or Landlord's agent during
          the term hereof, including but not limited to any agreement to accept
          surrender of the Premises or to amend or modify this Lease, shall be
          deemed to be binding upon Landlord unless such act or things shall be
          by an officer of Landlord or a party designated in writing by Landlord
          as so authorized to act. The delivery of keys to Landlord, or
          Landlord's agent, employees or officers shall not operate as a
          termination of this Lease or a surrender of the Premises. No payment
          by Tenant or receipt by Landlord of a lesser amount than the monthly
          rent herein stipulated shall be deemed to be other than on account of
          the earliest stipulated rent, nor shall any endorsement or statement
          on any check or any letter accompanying any check or payment as rent
          be deemed an accord and satisfaction and Landlord may accept such
          check or payment without prejudice to Landlord's right to recover the
          balance or such rent or pursue any other remedy available to Landlord.

               (j)  Landlord shall have the right to construct other buildings
          or improvements in any plaza or any other area designated by Landlord
          for use by tenants or to change the location, character or make
          alterations of or additions to any of said plazas or other areas.
          Landlord, during the entire term of this Lease, shall have the right
          to change the number and name of the Building at any time without
          liability to Tenant.

               (k)  Tenant acknowledges and agrees that it has not relied upon
         any statements, representations, agreements or warranties, except such
         as are expressed in this Lease.

               (l)  Time is of the essence hereof.

               (m)  (n) The word "Holidays" as used herein shall mean those days
          celebrated each calendar year as New Year's Day, Memorial Day,
          Independence Day, Labor Day, Thanksgiving, and Christmas and such
          other recognized national holidays to the extent office buildings are
          generally closed in the Denver metropolitan area.

               (n)  Tenant and Landlord and the party executing this Lease on
          behalf of each of them represent to each other that such party is
          authorized to do so by requisite action of the board of directors,
          members or partners, as the case may be, and agree upon request to
          deliver to each other a resolution or similar document to that effect.

               (o)  This Lease shall be governed by and construed in accordance
          with the laws of the State of Colorado.

               (p)  This Lease, together with Exhibits A. B. C. D and E,
                                              -------------------------
          attached hereto, contains the entire agreement of the parties and may
          not be amended or modified in any manner except by an instrument in
          writing signed by both parties. Tenant shall not record this Lease or
          a memorandum hereof.

               (q)  In the event Landlord makes available any area in the
          Building Complex for use as a health facility, Tenant agrees that
          Landlord shall not be liable for any injury or damage to persons or
          property arising out of the use of such health facility by Tenant, its
          employees or invitees, and further agrees to indemnify, defend and
          hold Landlord harmless against any claims, demands or damages
          associated therewith, including claims for personal injury and death.
          Tenant further agrees to execute and deliver to Landlord upon request,
          and indemnification agreement, in form acceptable to Landlord, as a
          condition precedent to use of any such health facility by Tenant and
          its employees and invitees.

                                      -29-
<PAGE>

               (r)  Tenant shall not use the name of the Building, the Building
          Complex or the development in which the Building is situated as part
          of its legal or trade name, nor for any purpose other than as an
          address for the business to be conducted by Tenant in the Premises.

               (s)  The submission or delivery of this document for examination
          and review does not constitute an option, an offer to lease space in
          the Building or an agreement to lease. This document shall have no
          binding effect on the parties unless and until executed by both
          Landlord and Tenant.

          39.  Hazardous Materials:
               -------------------

               (a)  Tenant shall at all times and in all respects comply with
          all federal, state and local laws, ordinances, rules and regulations
          ("Hazardous Materials Laws") relating to industrial hygiene,
          environmental protection or the use, analysis, generation,
          manufacture, storage, presence, disposal or transportation of any
          Hazardous Materials (as hereinafter defined).

               (b)  Except for normal and customary types and quantities of
          products which are used in the operation of a business office and
          which may be considered to be Hazardous Materials, Tenant shall not
          cause or permit any Hazardous Materials to be brought upon, kept,
          stored, generated, treated, manufactured, produced, disposed of,
          discharged, released, spilled or used in, on or about the Premises by
          Tenant or Tenant's affiliates, agents, employees, contractors,
          invitees, sublessees or assignees (collectively, the "Tenant
          Parties"). If Tenant or any Tenant Party breaches the obligation
          stated in the preceding sentence or if the presence of Hazardous
          Materials on the Premises caused or permitted by Tenant results in
          contamination of the Premises, the Building or any adjacent property,
          then Tenant shall indemnify, defend and hold harmless Landlord from
          and against any and all claims, judgments, actions, damages,
          penalties, fines, forfeitures, costs, expenses, liabilities or losses
          (including, without limitation, diminution in value of the Premises,
          the Building and/or adjacent property, damages for the loss or
          restriction on use of rentable or usable space of any amenity of the
          Premises, the building and/or adjacent property, damages arising from
          any adverse

               (c)  impact on marketing of the Premises, the Building and/or
          adjacent property, and sums paid in settlement of claims, attorneys'
          fees, consultant fees and expert fees and court costs) which arise
          during or after the Lease Term or any extension hereof, as a result of
          such breach. This indemnification of Landlord by Tenant includes,
          without limitation, costs incurred in connection with any
          investigation of site conditions or any cleanup, remedial, removal or
          restoration work required by any federal, state or local governmental
          agency or political subdivision because of any Hazardous Material
          present in the soil or ground water on or under the Premises, the
          Building and/or adjacent property. Without limiting the foregoing, if
          the presence of any Hazardous Material on the Premises caused or
          permitted by Tenant or any of the Tenant Parties results in any
          contamination of the Premises, the Building and/or adjacent property,
          Tenant shall promptly take all actions at its sole cost and expense as
          are necessary to return the Premises, the Building and/or adjacent
          property to the condition existing prior to the introduction of any
          such Hazardous Material to the Premises, the Building and/or adjacent
          property; provided that Tenant shall not take any remedial action in
          or about the Premises or the Building, nor enter into any settlement
          agreement, consent decree or other compromise with respect to any
          claims relating to Hazardous Materials in any way connected with the
          Premises or the Building, without first notifying Landlord of Tenant's
          intention to do so and affording Landlord the opportunity to appear,
          intervene or otherwise appropriately assert and protect Landlord's
          interest with respect thereto.

               (d)  As used in this Lease, the term "Hazardous Material" means
          any flammable item, explosive, radioactive material, hazardous or
          toxic substance, material or waste or related materials, including any
          substance defined as or included in the definition of "hazardous
          substances", "hazardous wastes", "infectious wastes", "hazardous
          materials" or "toxic substances" now or subsequently regulated under
          any federal, state or local laws, regulations or ordinances including,
          without limitation, oil, petroleum-based products, paints, solvents,
          lead, cyanide, DDT, printing inks, acids, pesticides, ammonia
          compounds and other chemical products, chemicals known to cause cancer
          or reproductive toxicity, asbestos,

                                      -30-
<PAGE>

          polychlorinated biphenyls (PCBs) and similar compounds, and including
          any other products and materials which are subsequently found to have
          adverse effects on the environment or the health and safety of
          persons.

               (e)  Tenant immediately shall notify Landlord in writing of: (i)
          any spill, release, discharge or disposal of any Hazardous Material
          in, on, under, around or about the Premises, the Building or any
          portion thereof of which Tenant has knowledge; (ii) any enforcement,
          cleanup, removal or other governmental or regulatory action
          instituted, contemplated, or threatened pursuant to any Hazardous
          Materials Laws and relating to the Premises or the Building of which
          Tenant has knowledge; (iii) any claim made or threatened by any person
          against Tenant, any of the Tenant Parties, the Premises, or the
          Building relating to damage, contribution, cost recovery,
          compensation, loss or injury resulting from or claimed to result from
          any Hazardous Materials of which Tenant has knowledge; and (iv) any
          reports made to any governmental agency or entity arising out of or in
          connection with any Hazardous Materials in, on, under, around or about
          or removed from the Premises or the Building of which Tenant has
          knowledge, including any complaints, notices, warnings, reports or
          asserted violations in connection therewith. Tenant also shall supply
          to Landlord as promptly as possible, and in any event within five (5)
          business days after Tenant first receives or sends the same, copies of
          all claims, reports, complaints, notices, warnings or asserted
          violations relating in any way to the Premises, the Building or the
          use or occupancy thereof by Tenant or any of the Tenant Parties. Upon
          any termination of this Lease, whether by lapse of time, cancellation
          pursuant to an election provided for herein, forfeiture or otherwise,
          Tenant shall immediately surrender possession of the Premises (and all
          improvements to the Premises which Tenant is not required to remove
          from the Premises pursuant to this Lease) to Landlord in full
          compliance with all Hazardous Materials Laws free of any Hazardous
          Material.

               (f)  Any material failure of Tenant to comply with the provisions
          of this Section 39 shall be a material default under this Lease.

               (g)  Landlord shall defend, indemnify and hold Tenant harmless
          from and against any and all losses, costs, (including reasonable
          attorney fees) liabilities and claims arising from any violations of
          Hazardous Materials Laws by Landlord and/or the existence of Hazardous
          Materials that are now or hereinafter become located in or on or under
          the Building Complex as a result of Landlord acts or negligence and
          shall assume responsibility and cost to remedy such violations and/or
          the existence of such Hazardous Materials provided that such
          violations or the existence of Hazardous Materials is not caused
          solely by Tenant.

               (h)  The provisions of this Paragraph 39 shall survive the
          expiration or earlier termination of the Lease Term.

          40.  Parking: Subject to Tenant's execution of a separate parking
               -------
agreement with the operator of the Building Parking Garage, Landlord agrees to
provide Tenant with the opportunity during the Term of this Lease to lease up to
forty-two (42) parking spaces in the Building Parking Garage. The allocation of
spaces between reserved and unreserved shall be subject to availability and
shall be arranged by Tenant with the garage operator prior to the Commencement
Date. The cost of such spaces shall be the prevailing market rates for
comparable parking spaces in the vicinity of the Building. During the Term of
the Lease, Tenant may reduce or increase the number of parking spaces up to the
maximum of forty-two (42), but in order to increase the number of spaces it must
give the garage operator at least sixty (60) days prior written notice of its
decision to lease additional parking spaces and any additional increase will be
subject to availability. Tenant acknowledges and agrees that during the baseball
season on days which baseball games commence after 5:30 p.m. that all of
Tenant's parking spaces shall be vacated prior to 5:30 p.m.; provided, however,
Tenant may purchase from the garage operator special game day parking privileges
for up to twelve (12) parking spaces, the cost of which shall be determined by
the garage operator, but shall not be more than that charged to other Building
tenants.

          41.  Right to Renew: Landlord hereby grants to Tenant one (1) option
               --------------
to renew this Lease for between a three (3) or five (5) year term (at the option
of Tenant) at the then prevailing market rate for comparable office

                                      -31-
<PAGE>

space in the downtown Denver, Colorado market area. The option to renew shall be
exercisable by Tenant only if Tenant is not in default of any material provision
under this Lease or in default of any monetary provision of this Lease, unless
the default is cured within the allowed time period. Tenant must give written
notice to Landlord of its intent to exercise the option and the length of the
term selected at least nine (9) months prior to the expiration of the then
current Term. If Tenant fails to provide such notice in accordance with this
paragraph, the option shall lapse and thereafter be null and void. As used
herein the prevailing term market rate shall mean the rate which Landlord or
other landlords have leased within the prior twelve (12) months for comparable
terms of comparable space in the Building and other comparable Class A buildings
in the central business district of Denver, Colorado. Upon exercising the
option, all terms and conditions during such extension period shall remain the
same as those set forth in the Lease, except that Annual Base Rent and Operating
Expenses. Within thirty (30) days after Landlord's receipt of Tenant's exercise
notice, Landlord shall provide Tenant with Landlord's reasonable opinion of
prevailing market rate. Upon Landlord's written notice of prevailing market rate
to Tenant, Tenant shall have fifteen (15) days to accept or reject such current
market rate in writing. If Tenant rejects Landlords opinion of the prevailing
market rate, the Landlord and Tenant shall have forty-five (45) days thereafter
to reach an agreement. If within said period Landlord and Tenant are unable to
agree this option to renew shall lapse and thereafter be null and void. In the
event Landlord and Tenant agree on the prevailing market rate, they shall
execute an amendment to the Lease providing for the renewal and the new Annual
Base Rent.

     42.  Letter of Credit:  Tenant at its expense shall deposit with Landlord
          ----------------
within two (2) weeks of Lease execution, as additional security to guaranty the
performance of Tenant under the terms of this Lease, an irrevocable letter of
credit in favor of Landlord in the amount of Seventy-Five Thousand and 00/100
Dollars ($75,000) in a form and from a bank recognized and acceptable to
Landlord. Provided that the base building improvements are sufficiently complete
to allow for the commencement of construction of the tenant improvements for the
Premises on or before January 10, 2000, Tenant shall as of December 15, 1999,
increase the letter of credit to a total of $525,000 (an additional $450,000).
In the event the base building improvements have not been sufficiently completed
by December 15, 1999, to allow for commencement of the tenant improvement by
January 3, 2000, the date to deliver the increased letter of credit shall be
extended by one day for each day of delay after December 15, 1999. Except as
provided below, the letter of credit shall remain on deposit with the Landlord
for the Term of the Lease. On each anniversary date of the Commencement Date, if
Tenant is not in material default under the terms of the Lease, the letter of
credit shall be reduced by the amounts and have the remaining balances indicated
below:

     Anniversary Date        Reduction             BALANCE
           1st                $ 50,000            $475,000
           2nd                $ 50,000            $425,000
           3rd                $200,000            $225,000
           4th                $112,500            $112,500
           5th                $112,500            $   0.00

Notwithstanding the foregoing, if at anytime after the thirty-sixth (36th) month
of the Lease, Tenant is able to demonstrate to Landlord, in Tenant's audited
financial statements, that it has maintained working capital of $5,000,000 or
more, as determined under generally accepted accounting principals, for a period
of twelve (12) consecutive months, the letter of credit shall be returned to
Tenant in exchange for the Security Deposit provided for in Paragraph 4 hereof.
If the letter of credit is to be renewed at any time during the Term of the
Lease, it shall be renewed not less than thirty (30) days prior to its
expiration. If for any reason the letter of credit is not renewed, other than
the expiration of the Lease, Landlord shall be entitled to draw on the entire
letter of credit. At the expiration of the Lease, if Tenant is not in default
under the terms of the Lease, Landlord shall return the letter of credit to
Tenant. Notwithstanding notice provisions contained elsewhere in this Lease, if
an event of default has occurred and the Landlord does not have sufficient time
to give notice to Tenant prior to the expiration of the letter of credit, the
Landlord shall be entitled to draw the letter of credit to the extent the amount
of the default claimed. The letter of credit shall be retained by Landlord as
security for payment by Tenant of the rents, all other payments herein agreed to
be paid by Tenant, the reimbursement of Landlord for the cost of tenant
improvements and leasing commissions, and for the faithful performance by Tenant
of the terms, provisions and conditions of this Lease. It is

                                      -32-
<PAGE>

agreed that Landlord may, at Landlord's option, at any time after a default by
Tenant under any of the terms, provisions, covenants or conditions of this
Lease, make one or more draws on the letter of credit to the extent of the
amount of the default and apply said sum or any part thereof towards the payment
of the rents and all other sums accrued and payable by Tenant under this Lease
(including, but not limited to, the cost of tenant improvement and leasing
commissions), which shall thereby be discharged only pro tanto; that Tenant
shall remain liable for any amounts that such letter of credit shall be
insufficient to pay; and that Landlord may exhaust any or all rights and
remedies against Tenant before resorting to said letter of credit, but nothing
herein contained shall require or be deemed to require Landlord to so do. The
letter of credit contemplates that in the event of multiple defaults, Landlord
shall be entitled to make multiple draws on the letter of credit. Nothing
contained in this paragraph shall be deemed or construed to constitute a
liquidated damages provision.

                                      -33-
<PAGE>

     IN WITNESS WHEREOF, Landlord and Tenant have executed this Lease the day
and year first above written.

                                   LANDLORD:

                                   CENTENNIAL VENTURE I, LLC


                                   By: /s/
                                       -----------------------------------------
                                   Title: General Manager
                                          --------------------------------------

                                   TENANT:

                                   WEBB INTERACTIVE SERVICES, INC.

                                   By: /s/  Lindley S. Branson
                                       -----------------------------------------
                                   Title: Ex. V.P. and General Counsel
                                          --------------------------------------

                                      -34-
<PAGE>

                              EXHIBIT A TO LEASE
                              ------------------

                            DESCRIPTION OF PREMISES

     This Exhibit supplements that certain Lease dated and executed concurrently
herewith by and between CENTENNIAL VENTURE I, LLC ("Landlord") and WEBB
INTERACTIVE SERVICES, INC. ("Tenant"), regarding Suite 600 consisting of
approximately 21,398 rentable square feet on the 6th floor of the Building as
depicted on the floor plan of the Building attached hereto as Exhibit A-1:

                                      A-1
<PAGE>

                              EXHIBIT A-l TO LEASE

21,398 RSF

                    [DIAGRAM OF FLOOR PLAN OF OFFICE SPACE]

                                      A-2
<PAGE>

                              EXHIBIT B TO LEASE
                              ------------------

                               LEGAL DESCRIPTION

Vacant Land Parcel:
------------------

A portion of Block "D," East Denver and Block "D" Hoyt & Robinson Addition to
Denver being a part of Section 28 and Section 33, Township 3 South, Range 68
West of the 6th Principal Meridian, being a part of the City and County of
Denver, State of Colorado, more particularly described as follows:

          Lots 23 to 30, Inclusive, Block "D," partly in East Denver and partly
          in Hoyt & Robinson's Addition to Denver, lying southeasterly of a line
          parallel with and 62.5 feet distant southeasterly, measured along the
          northeasterly line of said Block "D" of Hoyt & Robinson's Addition
          from the most northerly corner thereof, together with that certain
          16.0 feet wide alley vacated by Ordinance No. 475-1985 of the City and
          County of Denver adjoining said lots containing in all an area of
          25,437 square feet.

and

Parking Condominium Parcel:
--------------------------

Parking Condominium Unit C-1 to The Ice House Condominiums, according to
Condominium Map thereof, recorded April 1, 1997 under Reception No. 9700040664,
and Amended and Restated Condominium Map recorded December 12, 1997 under
Reception No. 9700168487, and Second Amendment to Amended and Restated
Condominium Map recorded November 18, 1998, in the records of the Clerk and
Recorder of the City and County of Denver, State of Colorado.

                                      B-1
<PAGE>

                              EXHIBIT C TO LEASE
                              ------------------

                          COMMENCEMENT DATE AGREEMENT

     THIS COMMENCEMENT DATE AGREEMENT ("Agreement") is given by WEBB INTERACTIVE
SERVICES, INC. ("Tenant") to CENTENNIAL VENTURE I, LLC ("Landlord"), with
respect to that certain Lease Agreement dated _____, 1999 ("Lease"), under which
Tenant has leased from Landlord certain premises known as Suite _____
("Premises") in 1899 Wynkoop Building at 1899 Wynkoop Street, Denver, Colorado
("Building").

     In consideration of the mutual covenants and agreements stated in the
Lease, and intending that this Agreement may be relied upon by Landlord and any
prospective purchaser or present or prospective mortgagee, deed of trust
beneficiary or ground lessor of all or a portion of the Building certifies as
follows:

     1.   The Commencement Date of this lease is __________, 2000.

     2.   The Expiration Date of the Lease is _______________, 20____.

     3    The Premises contain 21,398 rentable square feet of space.

     4.   The Expense Stop is $6.50.

     5.   The Base Rent for the Premises is:

                         MONTHLY             ANNUAL
     PERIOD              BASE RENT           BASE RENT
     Months 1-2          $46,362.33          See Paragraph 3
     Months 3-36         $46,362.33          $556,348.00
     Months 37-62        $49,928.67          $599,144.00

     Executed this _________ day of _____________, 20____.

                                        TENANT:
                                        WEBB INTERACTIVE SERVICES, INC.


                                        By: ____________________________________
                                        Printed Name:___________________________
                                        Title:__________________________________

                                      C-1
<PAGE>

                              EXHIBIT D TO LEASE
                              ------------------

                                 1899 WYNKOOP

                                  WORK LETTER

     1.   Conflicts; Terms. If there is any conflict or inconsistency between
          ----------------
the provisions of the Lease and those of this Exhibit D ("Work Letter"), the
provisions of this Work Letter will control. Except for those terms expressly
defined in this Work Letter, all initially capitalized terms will have the
meanings stated for such terms in the Lease.

               (a)  "Scheduled Commencement Date" means May 1, 2000.

               (b)  "Landlord's Representative" means Randy Nichols.

               (c)  "Tenant's Representative" means Doug WuIf.

               (d)  "Schematic Plan Approval Date" means November 12, 1999.

               (e)  "Budget Pricing" means the estimate of the Total Cost based
          upon the Tenant's Pricing Plans.

               (f)  "Budget Pricing and Pricing Plan Approval Date" means
          November 30, 1999.

               (g)  "Working Drawings and Final Pricing Approval Date" means
          December 30, 1999.

               (h)  "Landlord's Allowance" means $25.50 per rentable square foot
          of the Premises (a total of $545,649.00) to be used solely for
          Leasehold Improvements to the Premises including Schematic Plans,
          Construction Documents, permit fees, construction supervision fee,
          construction of work above the ceiling grid and all slab to slab
          improvements to the Premises (i.e. HVAC, sprinklers, lighting, ceiling
          grid and acoustical tiles, etc.). Tenant acknowledges and agrees that
          Landlord may, in its discretion, allocate the Landlord's Allowance
          towards the payment of certain of the Leasehold Improvements, which
          allocation shall be made in the construction contract.

               (i)  "Base Building" means those items listed on Exhibit D-1
          which shall be constructed by Landlord at its sole cost and expense
          and shall not be charged against the Landlord's Allowance.

               (j)  "Leasehold Improvements" means all alterations, leasehold
          improvements and installations to be constructed or installed by
          Landlord or Tenant in the Premises according to this Work Letter other
          than Base Building Improvements.

               (k)  "Schematic Plans" means space plans and general
          specifications for the Leasehold Improvements.

               (l)  "Construction Documents" means complete space plans, working
          drawings, construction plans and specifications for the Leasehold
          Improvements, which shall be prepared at Landlord's sole cost and
          expense. The preparation of mechanical, plumbing and electrical
          drawings shall be coordinated through Landlord's architect. All
          engineered drawings shall be prepared by the Landlord's engineers.

               (m)  "Total Cost" means the total cost of obtaining all Schematic
          Plans, Construction Documents, necessary permits, constructing and
          installing the Leasehold Improvements in the Premises, and providing
          any Building services required during construction (such as
          electricity and other utilities, refuse removal and housekeeping).

                                      D-1
<PAGE>

     2.   Landlord's Obligations.  Landlord will proceed to complete the Base
          ----------------------
Building and the Premises according to this Work Letter and tender possession of
the Premises to Tenant when Base Building and the Leasehold Improvements have
been completed to the extent that only punch list items, which would not
materially interfere with Tenant's use and enjoyment of the Premises, require
completion or correction. Tenant will accept the Premises when Landlord tenders
possession, provided that the Premises has been made ready for occupancy.
Landlord and Tenant agree that all alterations, improvements and additions made
to the Premises according to this Work Letter, whether paid for by Landlord or
Tenant, will, without compensation to Tenant, become Landlord's property upon
installation and will remain Landlord's property at the expiration or earlier
termination of the Term.

     3.   Representatives. Landlord appoints Landlord's Representative to act
          ---------------
for Landlord in all matters covered by this Work Letter. Tenant appoints
Tenant's Representative to act for Tenant in all matters covered by this Work
Letter. All inquiries, requests, instructions, authorizations and other
communications with respect to the matters covered by this Work Letter will be
made to Landlord's Representative or Tenant's Representative, as the case may
be. Tenant will not make any inquiries of or requests to, and will not give any
instructions or authorizations to, any other employee or agent of Landlord,
including Landlord's architect, engineers and contractors or any of their agents
or employees, with regard to matters covered by this Work Letter. Either party
may change its Representative under this Work Letter at any time by 3 days prior
written notice to the other party.

     4.   Construction Schedule. Attached hereto as Exhibit D-2 is the schedule
          ---------------------
for construction of the Leasehold Improvements (the "Construction Schedule").
The Tenant has reviewed and approved the Construction Schedule and acknowledges
that delays in meeting the scheduled dates, if caused by Tenant, will result in
the inability of the contractor to complete the Leasehold Improvements by the
Scheduled Commencement Date and that each day of delay caused by Tenant's
actions or omissions shall result in a day for day extension of Landlord's
obligations and responsibilities under the Lease and this Exhibit D, including
Landlord's obligations under subparagraph 2(c)(6) of the Lease.

     5.   Schematic Plans. Tenant will cooperate with Landlord and W. E. Kieding
          ---------------
("Kieding") and submit all information necessary for preparation of the
Schematic Plans. Subject to Tenant's cooperation in the preparation of the
Schematic Plans, at least three (3) business days prior to the Schematic Plan
Approval Date, Kieding shall deliver to Tenant for its approval a copy of the
Schematic Plans for the Premises. Within three (3) business days after receipt
of the Schematic Plans, but not later than the Schematic Plan Approval Date,
Tenant will either approve the same in writing or notify Landlord in writing of
how the proposed Schematic Plans are inconsistent with the design information
supplied by Tenant and how the Schematic Plans must be changed in order to
overcome Tenant's objections. Each day following the later of the third (3rd)
business day after the Tenant's receipt of the Schematic Plans or the Schematic
Plan Approval Date until Tenant approves them shall be a day of Tenant's delay.
Upon receipt of Tenant's notice of objections, W. E. Kieding shall prepare
revised Schematic Plans according to such notice and submit the revised
Schematic Plans to Tenant. Upon submittal to Tenant of the revised Schematic
Plans, and upon submittal of any further revisions, the procedures described
above will be repeated. If the revised Schematic Plans, or any further
revisions, are consistent with the design information and all requirements
identified in Tenant's prior notice(s) of objections, then each day following
Landlord's receipt of Tenant's notice of any additional objections until the day
on which Landlord receives Tenant's written approval of the Schematic Plans will
be a day of Tenant's delay. Landlord and Tenant acknowledge and agree that they
have each approved the Schematic Plan within the time deadlines set forth in
this Paragraph 5.

     6.   Budget Pricing. At such time as Schematic Plans have been approved in
          --------------
writing by Tenant, Kieding will prepare Pricing Plans for submission to the
contractor in order to obtain Budget Pricing. On or before three (3) business
days prior to the Budget Pricing and Plan Approval Date, Kieding shall deliver
to Tenant the Budget Pricing and Pricing Plan for Tenant's approval. If the
Budget Pricing is less than or equal to Landlord's Allowance, then Tenant will
be deemed to have approved the Budget Pricing and Pricing Plan. If the Budget
Pricing is greater than Landlord's Allowance, then Tenant, at Tenant's option,
may either approve the Budget Pricing in writing or elect to eliminate or revise
one or more items shown on the Pricing Plans so as to reduce the Budget Pricing
and then approve in writing the reduced Budget Pricing (based on the revised
Pricing Plans). If the original Budget Pricing is greater than Landlord's
Allowance, then each day following the later of three (3) business days after
Tenant's receipt of such Budget Pricing and Pricing Plan or the Budget Pricing
and Pricing Plan Approval Date

                                      D-2
<PAGE>

until the day Landlord receives Tenant's written approval of the Budget Pricing
(as the same may have been revised) and the Pricing Plan will be a day of
Tenant's delay.

     7.   Construction Documents; Final Pricing. At such time as the Budget
          -------------------------------------
Pricing and Pricing Plan have been approved (or deemed approved) by Tenant,
Landlord will cause its architect and engineer to prepare the Working Drawings
based strictly on the approved Pricing Plans. At such time as the Working
Drawings have been prepared, Landlord will obtain bids from its general
contractor (The Neenan Company) for the construction or installation of the
Leasehold Improvements according to the Working Drawings. Each trade shall be
bid by a minimum of three (3) subcontractors unless otherwise approved by
Tenant. The Neenan Company may select its mechanical, electrical, plumbing and
fire/safety contractors working on the Building Complex to complete the
Leasehold Improvements; provided that such contractors bids must be for amounts
which are comparable to third party bids obtained by The Neenan Company. At
least three (3) business days before the Working Drawings and Final Pricing
Approval Date, Landlord shall cause to be delivered to Tenant the Working
Drawings and Final Pricing for Tenant's approval. If the Final Pricing is less
than or equal to the Budget Pricing approved by Tenant, then Tenant will be
deemed to have approved the Final Pricing and the Working Drawings. If the Final
Pricing is greater than the Budget Pricing approved by Tenant, then Tenant, at
Tenant's option, may either approve the Final Pricing in writing or elect to
eliminate or revise one or more items shown on the Working Drawings so as to
reduce the Final Pricing and then approve in writing the reduced Final Pricing
(based on the revised Working Drawings). If the Final Pricing approved or deemed
approved by Tenant is greater than Landlord's Allowance, then Tenant will
immediately deposit with Landlord an amount ("Construction Deposit") equal to
the difference between Landlord's Allowance and the approved Final Pricing. Each
day following the later of the third (3rd) business day after Tenant's receipt
of the Final Pricing and Working Drawings or the Working Drawings and Final
Pricing Approval Date until the day on which Landlord has received Tenant's
written approval of the Working Drawings, Final Pricing (if required) and
Landlord has received the Construction Deposit (if required) will be a day of
Tenant's delay. Notwithstanding the provisions of Paragraphs 5 and 6 of this
Work Letter, if Tenant Approves the Working Drawings and Final Pricing by the
Working Drawings and Final Pricing Approval Date, the days of Tenant's delay
accumulated prior to such date shall be disregarded.

     8.   Building Permit; Construction of Leasehold Improvements. At such time
          -------------------------------------------------------
time as Tenant has approved (or is deemed to have approved) the Working Drawings
and Final Pricing, has made any required Construction Deposit, and the Building
Permit has been received, Landlord will cause the Leasehold Improvements to be
constructed or installed in the Premises in a good and workmanlike manner and
according to the Construction Documents and all Laws. Upon substantial
completion of the construction and installation of the Leasehold Improvements
and prior to Tenant's occupancy of the Premises, Tenant will pay to Landlord the
amount, if any, by which the Total Cost exceeds the sum of the Landlord's
Allowance and the Construction Deposit. Tenant will not be entitled to any
credit if Landlord's Allowance exceeds the Total Cost. Neenan's fees shall be 7%
for general conditions and 5% for overhead and profit. Landlord or its
affiliates shall receive a construction supervision fee equal to three percent
(3%) of the Total Cost which amount shall be paid from the Landlord's Allowance.

     9.   Change Orders. Tenant's Representative may authorize changes in the
          -------------
work during construction only by written instructions to Landlord's
Representative on a form approved by Landlord. All such changes will be subject
to Landlord's prior written approval according to Paragraph 12 below. Prior to
commencing any change, Landlord will prepare and deliver to Tenant, for Tenant's
approval, a change order ("Change Order") identifying any additional time
required to complete the Leasehold Improvements, and the effect on the Scheduled
Commencement Date and the total cost or cost savings resulting from such change,
which will include associated architectural, engineering and construction
contractor's fees, and an amount sufficient to reimburse Landlord for overhead
and related expenses incurred in connection with the Change Order. If Tenant
fails to approve and pay for such Change Order within three (3) business days
after delivery by Landlord, Tenant will be deemed to have withdrawn the proposed
change and Landlord will not proceed to perform the change. Upon Landlord's
receipt of Tenant's approval and payment, Landlord will proceed to perform the
change.

     10.  Additional Tenant Work. If Tenant desires any work in addition to
          ----------------------
the Leasehold Improvements to be performed in the Premises ("Additional Tenant
Work"), Tenant, at Tenant's

                                      D-3
<PAGE>

expense, will cause plans and specifications for such work to be prepared either
by Landlord's architect or engineer or by consultants of Tenant's own selection.
All plans and specifications for Additional Tenant Work will be subject to
Landlord's approval according to Paragraph 12 below. If Landlord approves
Tenant's plans and specifications for any Additional Tenant Work, Landlord will,
subject to the following terms and conditions, grant to Tenant and Tenant's
agents a license to enter the Premises prior to the Commencement Date in order
that Tenant may perform or cause to be performed the Additional Tenant Work
according to the plans and specifications previously approved by Landlord:

          (a)  Tenant will give Landlord not less than three (3) business days
     prior written notice of the request to have such access to the Premises,
     which notice must contain or be accompanied by: (i) a description and
     schedule for the work to be performed by those persons and entities for
     whom such early access is being requested; (ii) the names and addresses of
     all contractors, subcontractors and material suppliers for whom such access
     is being requested; (iii) the approximate number of individuals, itemized
     by trade, who will be present in the Premises; (iv) copies of all contracts
     pertaining to the performance of the work for which such early access is
     being requested; (v) copies of all licenses and permits required in
     connection with the performance of the work for which such access is being
     requested; (vi) certificates of insurance and instruments of
     indemnification against all claims, costs, expenses, damages, suits, fines,
     penalties, actions, causes of action and liabilities which may arise in
     connection with such work; (vii) assurances of the availability of funds
     sufficient to pay for all such work, if such assurances are requested by
     Landlord; and (viii) if requested by Landlord full lien waivers from all
     contractors and material men employed by Tenant. Each of such matters will
     be subject to Landlord's approval, which approval will not be arbitrarily
     withheld.

          (b)  Such early access is subject to scheduling by Landlord.

          (c)  Tenant's agents, contractors, workers, mechanics, suppliers and
     invitees must work in harmony and not interfere with Landlord and
     Landlord's agents in doing work in the Premises and in other premises and
     Common Areas of the Building, or the general operation of the Building. If
     at any time such entry causes or threatens to cause disharmony or
     interference, including labor disharmony, Landlord may immediately withdraw
     Tenant's license for access.

          (d)  If Landlord's work in the Premises and Tenant's work in the
     Premises (under such license granted by Landlord) progress simultaneously,
     Landlord will not be liable for any injury to person or damage to property
     of Tenant, or of Tenant's employees, licensees or invitees, from any cause
     whatsoever occurring upon or about the Premises, and Tenant will indemnify
     and save Landlord harmless from any and all liability and claims arising
     out of or connected with any such injury or damage.

          (e)  Tenant agrees that it is liable to Landlord for any damage to the
     Premises or any portion of the work in the Premises caused by Tenant or any
     of Tenant's employees, agents, contractors, workers or suppliers.

     11.  Punch List. Unless otherwise agreed to by Landlord and Tenant or as
          ----------
to any latent defects of which Tenant notifies Landlord in writing within nine
(9) months after the Commencement Date, Tenant's taking possession of any
portion of the Premises at the time as the Premises are ready for occupancy will
be conclusive evidence that the Premises is in good order and satisfactory
condition when Tenant took possession; except as to any items requiring
correction or completion identified on a punch list prepared and signed by
Landlord's Representative and Tenant's Representative after an inspection of the
Premises by both such parties prior to Tenant taking possession (the
"Preliminary Punch List") and such other items as are identified on a final
punch list prepared and signed by Landlord's Representative and Tenant's
Representative within seven (7) business days after the Premises are delivered
to Tenant for occupancy (the "Final Punch List"). Final Punch List items shall
not include items which were damaged during Tenant's move into the Premises or
painting which should have been specified on the Preliminary Punch List. It is
intended that the Final Punch List will be for items which Tenant could not have
reasonably been expected to discover prior to moving into the Premises.
Landlord's general contractor will, within 10 days after execution of each punch
list, begin correction or completion of any items specified on such punch list
and will complete such work in a prompt and diligent manner. Landlord will not
be responsible for any items of damage caused by Tenant, its agents, independent
contractors or suppliers. No promises to alter, remodel

                                      D-4
<PAGE>

or improve the Premises or Building and no representations concerning the
condition of the Premises or Building have been made by Landlord to Tenant other
than as may be expressly stated in the Lease (including this Work Letter).

     12.  Landlord's Approval. All Schematic Plans, Construction Documents and
          -------------------
Change Orders; and any drawings, space plans, plans and specifications for any
Additional Tenant Work or any other improvements or installations in the
Premises, are expressly subject to Landlord's prior written approval. Landlord
may withhold its approval of any such items that require work which:

               (a)  exceeds or adversely affects the capacity or integrity of
     the Building's structure or any of its heating, ventilating, air
     conditioning, plumbing, mechanical, electrical, communications or other
     systems;

               (b)  is not approved by the holder of any encumbrance;

               (c)  would not be approved by a prudent owner of property similar
     to the Building;

               (d)  violates any agreement which affects the Building or binds
     Landlord;

               (e)  Landlord reasonably believes will increase the cost of
     operating or maintaining any of the Building's systems;

               (f)  Landlord reasonably believes will reduce the market value of
     the Premises or the Building at the end of the Term;

               (g)  does not conform to applicable building code or is not
     approved by any governmental authority having jurisdiction over the
     Premises;

               (h)  does not meet or exceed Building Standard; or

               (i)  Landlord reasonably believes will infringe on the
     architectural or historical integrity of the Building.

     13.  Tenant's Delays. Except as provided in Paragraph 2 of the Lease,
          ---------------
the Term of the Lease (and therefore Tenant's obligation for the payment of Base
Rent) will not commence until the Premises are delivered to Tenant for
occupancy; provided, however, that if Landlord is delayed in substantially
completing such work as a result of:

               (a)  any Tenant delays described in Paragraphs 4, 5, 6, 7, or 8
     above;

               (b)  Tenant's request for materials or installations as a part of
     the Leasehold Improvements that are other than Building Standard materials
     or installations;

               (c)  any Change Orders or changes in any drawings, plans or
     specifications requested by Tenant;

               (d)  Tenant's failure to review or approve in a timely manner any
     item requiring Tenant's review or approval;

               (e)  performance of any Additional Tenant Work or any failure to
     complete or delay in completion of such work; or

               (f)  any other act or omission of Tenant or Tenant's architects,
     engineers, contractors or subcontractors (all of which will be deemed to be
     delays caused by Tenant);

                                      D-5
<PAGE>

     then the Commencement Date will be adjusted as provided in Paragraph 2 of
the Lease and Landlord's obligations and responsibilities shall be extended as
provided in Paragraph 4 of this Exhibit D.

     14.  General. No approval by Landlord or Landlord's architect or engineer
          -------
of any drawings, plans or specifications which are prepared in connection with
construction of improvements in the Premises will constitute a representation or
warranty by Landlord as to the adequacy or sufficiency of such drawings, plans
or specifications, or the improvements to which they relate, for any use,
purpose or condition, but such approval will merely be the consent of Landlord
to the construction or installation of improvements in the Premises according to
such drawings, plans or specifications. Failure by Tenant to pay any amounts due
under this Work Letter will have the same effect as failure to pay Base Rent
under the Lease, and such failure or Tenant's failure to perform any of its
other obligations under this Work Letter will constitute a Default under
Paragraph 19 of the Lease, entitling Landlord to all of its remedies under the
Lease as well as all remedies otherwise available to Landlord.

     15.  Construction Warranty. Landlord warrants to Tenant that the Leasehold
          ---------------------
Improvements will be completed in a good and workmanlike manner in accordance
with the Construction Documents and (subject to subparagraph 10(c) of the Lease)
all laws, and that, upon completion of the Leasehold Improvements, the same
shall be free from material defect arising out of defects in design or materials
or improper workmanship for a period of one year from the Commencement Date. In
addition, in the event that in connection with the portions of the Leased
Premises which are the responsibility of the Tenant to maintain, repair and/or
replace, any contractors, subcontractors, or suppliers that make any warranties
with respect to workmanship or materials which extend beyond the period of the
Landlord's warranty set forth above in this paragraph, Landlord shall make the
same available to Tenant upon the expiration of the warranty period. Without
limiting the generality of the foregoing, if, within one (1) year after the date
of substantial completion of the Leasehold Improvements, any part of the
Leasehold Improvements is found to be not in accordance with the requirements of
this Lease or the Construction Documents or laws, Landlord shall correct it
promptly after receipt of written notice from Tenant to do so. This obligation
under this paragraph shall survive acceptance of such work. Landlord partially
shall bear the cost of correcting destroyed or damaged construction, whether
completed or completed, caused by Landlord's correction or removal of the work
which is not in accordance with the requirements of this Lease, the Construction
Documents or laws. In order to cause Landlord to honor the warranty contained in
this paragraph Tenant must give written notice to Landlord specifying the defect
within thirteen (13) months after the Commencement Date, after which date this
warranty shall lapse.

     Landlord further warrants to Tenant that the Base Building will be
completed in a good and workmanlike manner in accordance with the plans and
specifications described on Exhibit D-1 and all laws.


Landlord:                                    Tenant:
CENTENNIAL VENTURE I, LLC                    WEBB INTERACTIVE SERVICES, INC.

By: /s/                                      By: /s/ Lindley S. Branson
    ---------------------------------            -------------------------------

Title: General Manager                       Title: Ex. V.P. and General Counsel
       ------------------------------               ----------------------------

                                      D-6
<PAGE>

                       LEASEHOLD IMPROVEMENTS STANDARDS

      Scope of Work Definition Base Building vs. Tenant Improvement Work

<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------------------------------------
ITEM                       BASE BUILDING                                   TENANT IMPROVEMENTS
----------------------------------------------------------------------------------------------------------------------------
<S>                        <C>                                             <C>
Ceilings                   a. No requirement in Tenant Premises            a.   Furnish and install 2' x 4'
                                                                                acoustical ceiling grid Chicago Metallic
                                                                                White 15/16" intermediate weight throughout
                                                                                Tenant's Premises.  Furnish and install 2' x
                                                                                4' acoustical ceiling tile (not yet
                                                                                selected) equal to Armstrong's Second Look
                                                                                II on each floor at a height of 9'0".

                           b. Core and shell shall provide                 b.   No. requirement.
                              drywall ceilings in restroom areas and
                              decorative drywall ceilings in tenant
                              lobby areas.

                           c. No requirement.                              c.   Provide upgraded ceiling systems as
                                                                                required by tenant's space plan.

Core Service Areas         a. Elevators, toilet rooms,                     a.   No requirements.
                              telephone, electrical rooms, stairwells,
                              janitor closets, service entry and
                              mechanical rooms are to be provided
                              complete.

Doors, Frames and          a. Furnish and install oak, birch or            a.   T.I. will include any required
Hardware                      maple veneer doors (3'-0" x 8'-10") in            corridor construction, including corridor
                              hollow metal welded frames at all public          doors.
                              building areas (painted to match standard
                              tenant door frame colors).  Service core
                              doors will be 3' x 9' solid core set in
                              welded hollow metal frames.  Building
                              entry and service core doors will be
                              equipped with mortise locks.  All locks
                              should have removable cores.  Ground floor
                              service core doors to be hollow metal
                              doors in painted hollow metal frames.

                           b. No requirement.                              b.   Furnish, install and finish solid
                                                                                core natural finish flush honey colored
                                                                                maple doors (3'0" x 9'0" nominal), aluminum
                                                                                metal frames as required by tenant's space
                                                                                plan.  Polished chrome hardware with lever
                                                                                handled and cylindrical locks or passage
                                                                                sets.

                           c. No requirement.                              c.   Furnish and install solid core
                                                                                natural finished flush honey colored maple
                                                                                tenant entry door (3'0" x 9'0"), per code,
                                                                                in aluminum metal frames with sidelights
                                                                                extending the full door height and glass is

                                                                                16" in width.  Satin bronze finish on all
</TABLE>

                                      D-7
<PAGE>

<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------------------------------------
ITEM                       BASE BUILDING                                   TENANT IMPROVEMENTS
<S>                        <C>                                             <C>
                                                                                door hardware.  Provide and install lever
                                                                                handle, mortise licks and closers on all
                                                                                tenant entry doors.  All locks to have
                                                                                removable cores.  Manufacturer of locks must
                                                                                be compatible with Landlord's locking system
                                                                                for the base building

                           d. Furnish and install proximity                d.   No requirement.  At Tenant's
                              type card access, electric locks for after        expense; Tenant may tie into Landlord's card
                              hour security at each of the building             access system.
                              entrances. (per allowance in contract).

Electrical                 a. Furnish and install a complete               a.   No requirement.
                              244/480 volt, 3 phase, 4 wire building power
                              distribution system.

                              2.0 watt per SF allocated for lighting

                              7.0 watts per SF allocated for office
                              equipment loads (including HVAC)

                           b. Furnish and install on 277 volt              b.   Lighting circuits and switching
                              lighting panel in the central electrical          distributed from central panel to tenant
                              room on each floor.                               fixtures.

                           c. No requirement.                              c.   Furnish and install light fixtures
                                                                                as required by tenant's space plan.
                                                                                Fluorescent fixtures are to be 2' x 4',
                                                                                18 cell 3" deep parabolic and equipped with
                                                                                three (3) T8 lamps and electronic ballast.
                                                                                Fixture density at 1:80 RSF (minimum). Furnish
                                                                                and install connection to J-box, switching and
                                                                                accent lighting.

                           d. Furnish and install lighting in              d.   No requirement.
                              base building rooms and all common areas.

                           e. Furnish and install (1) step down            e.   Furnish and install branch circuits
                              transformer and one 120/208 v. panel at           for 120V power to tenant spaces from Elec.
                              each floor for tenant power circuits.             Rooms.  Furnish and install convenience
                                                                                outlets (power poles not permitted) as
                                                                                desired  along with any additional
                                                                                distribution panels or step down
                                                                                transformers.

                           f. Furnish and install all code                 f.   Furnish and install code required
                              required exit and emergency lighting for          exit and emergency lighting for all tenant
                              all public areas.                                 areas.  Same or Landlord specs.

                           g. Furnish and install adequate                 g.   Furnish and install3/4" conduit for
                              telephone chases to the telephone rooms on        horizontal distribution from telephone
                              each floor and from the main telephone            closet on each floor to accessible ceiling
                              room at ground level.  Provide 4' x 8' x          space in each tenant space.
                              3/4" plywood phone board in all telephone
                              rooms.
</TABLE>

                                      D-8
<PAGE>

<TABLE>
<CAPTION>
-------------------------------------------------------------------------------------------------------------------------------
ITEM                       BASE BUILDING                                      TENANT IMPROVEMENTS
<S>                        <C>                                                <C>
                           h. Furnish and install fire                        h.   Fire management provisions, if any,
                              management systems as required by code,              in addition to code requirements.
                              including horn and strobe devices on each
                              floor.

                           i. Furnish exterior building accent                i.   No requirements.
                              lighting per allowance as stated in
                              contract.

Elevators                  a. Furnish and install four electric   a.          No requirement.
                              traction passenger elevators with a speed
                              of 350' per minute.  One of the cabs will
                              be a dual service cab also serving as a
                              freight elevator.  All passenger elevators
                              will have a 3,500 lb. capacity.

                           b. Furnish and install custom                      b.   No requirement.
                              interior cab wall ceiling and floor
                              finishes per allowance incl. in contract
                              in office elevators and standard cab
                              finishes in the parking elevators.

                           c. Two (2) hydraulic elevators with                c.   No requirements.
                              2,500 lb. capacity two service the parking
                              garage.  These cabs will have a speed of
                              150' per minute.

Fire Protection            a. Furnish and install complete fire               a.   Relocate or add sprinkler for
Sprinkler System              protection system per NFPA re-requirements           proper coverage as dictated by the tenant's
                              for office occupancy                                 space plan.

Floor Covering             a. Furnish and install all stone,                  a.   Furnish and install all stone,
                              carpet and tile flooring per design and              carpet, tile flooring, ceilings, all light
                              allowances in contract at ground floor and           fittings, and all wall finishes in upper
                              restrooms.  Upper elevator lobby walls to            elevator lobbies.
                              have drywall prepared for painting.

                           b. Provide smooth trowelled concrete               b.   Furnish and install floor coverings
                              slabs ready for finish.                              for all Tenant areas.  Carpet shall be
                                                                                   Mannington Belwede II, 32 oz. for cut pile
                                                                                   and Manning ton
                                                                                   Aspects II for level loop upgrade, or
                                                                                   Landlord approved equal.

HVAC                       a. The cooling ratio is approx. 425                a.   Furnish and install separate air
                              GSF/ton and is based on calculations using        conditioning on air handling units for
                              the building envelope and internal loads,         nonstandard loads (i.e. computer room).
                              as described in the mechanical systems
                              narrative provided for the Schmatic
                              Design.  The cooling tower has spare
                              capacity for 20 tons/floor of additional
                              tenant cooling on Floors Two through
                              Nine.  The HVAC systems will meet ASHRAE
</TABLE>

                                      D-9
<PAGE>

<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------------------------------------
ITEM                       BASE BUILDING                                   TENANT IMPROVEMENTS
<S>                        <C>                                             <C>
                              standards for ventilation, indoor air
                              quality, heating and cooling.  The core
                              and shell design will accommodate 1,100
                              s.f. tenant improvement zones.  After
                              hours cooling will be available for all
                              tenants on a floor-by-floor basis.  the
                              central plant will modulate to meet the
                              requirements of the after-hours part load
                              operation.

                           b. There will be a primary trunk                b.   No requirement.
                              duct from the air handlers to the vicinity
                              of each zone.

                           c. Furnish and install base building            c.   Provide modifications as required
                              energy management system with DDC                 by tenant's space plan.  Provide DDC
                              temperature control system.                       temperature control connection to all
                                                                                terminal devices.

                           d. The only exhaust systems being               d.   There is no general exhaust system
                              provided in the core and shell are toilet         planned in the core and shell for such
                              exhaust, life safety exhaust and parking          spaces as conference rooms, etc.  since this
                              garage exhaust, as required for the               facility is a non-smoking facility, it is
                              applicable codes.                                 our assessment that a general exhaust system
                                                                                is unnecessary. If additional air flow is
                                                                                required in spaces such as conference rooms,
                                                                                then transfer fans can be installed and
                                                                                discharge the air into the return air plenum
                                                                                to be cooled by air handling unit cooling
                                                                                coil.

Interior Columns           a. To be framed with metal studs.               a.   Furnish and install 5/8" gypsum
                                                                                board to columns.  Tape and sand smooth.
                                                                                Apply paint/wall covering and base.

Interior Partitions        a. No requirement.                              a.   Construct gypsum board partitions
                                                                                consisting of 5/8" sheetrock on 3-5/8" metal
                                                                                studs set 24" O.C. on center, as required by
                                                                                tenant's space plan.  Finish as desired.
                                                                                Apply paint/wall covering and base.
                                                                                Partitions shall run to the acoustical
                                                                                ceiling except in areas approved by Landlord.

                           b. No requirement.                              b.   Construct required building
                                                                                corridor walls to underside of structure
                                                                                with gypsum wall board both sides (rated - 1
                                                                                hour).  5/8" sheetrock on 3 5/8" metal studs
                                                                                set at 24" on center.

Perimeter Walls            a. Provide a framed & insulated                 a.   Furnish and install 5/8" gypsum
                              surface ready to receive gypsum board.            board walls at exterior, taped and sanded
                                                                                smooth.  Apply paint/wall covering and
</TABLE>

                                     D-10
<PAGE>

<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------------------------------------
ITEM                       BASE BUILDING                                   TENANT IMPROVEMENTS
<S>                        <C>                                             <C>
                                                                                base.

                           b. No window sills are provided in              b.   Provide sills.
                              core & shell scope of work.  Framing at
                              perimeter wall included.

                           c. Furnish and install building                 c.   No requirement.
                              directory (per allowance in contract

                           d. Furnish and install glass                    d.   No requirement.
                              entrance doors.

                           e. Furnish and install security desk            e.   No requirement.
                              (per allowance in contract).

Plumbing                   a. Furnish and install complete                 a.   No requirement.
                              plumbing in core service areas.  Ladies
                              room to have four water closets and two
                              sinks and the men's room a combination of
                              four water closets and urinals and two
                              sinks.

                           b. Furnish and install (2) electric             b.   No requirement.
                              water coolers adjacent to public toilet
                              rooms at each floor 2-9.

                           c. Furnish (2) two tenant wet stub              c.   Furnish and install convenience
                              groups, one at each side of core near             sinks, water supply to coffee/vending areas,
                              restroom block on each office floor.  Each        etc., as needed.
                              stub group shall have a cold water, hot
                              water, 4" waste and a vent line.

Signage                    a. Furnish and install general                  a.   Furnish and install identification
                              identification/ directional signage at            signage at tenant entrances.
                              toilet rooms and exit stairwells.

                           b. Furnish and install upper                    b.   No requirement.
                              elevator lobby

                           c. Furnish and install exterior                 c.   No requirement.
                              signage for building identification (per
                              allowance in contract)

Stairs                     a. Furnish and install painted metal            a.   No requirement.
                              pan and riser with poured concrete.
                              Painted metal stringer and railings.

                           b. Paint stair walls.  Furnish and              b.   No requirement.
                              install surface-mounted lighting at stair
                              landings.

Structure                  a. Structural steel frame and                   a.   No requirement.
                              composite steel and concrete floor
                              structure (fire resistant to code
                              requirements).

                           b. Supported live load capacity of              b.   No requirement.
                              50 lbs. per SF and a partition load of
                              20 lbs.
</TABLE>

                                     D-11
<PAGE>

<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------------------------------------
ITEM                       BASE BUILDING                                   TENANT IMPROVEMENTS
<S>                        <C>                                             <C>
                              per SF have been allowed which will
                              provide additional areas located near the
                              core with 250 lbs. loading capacity in
                              these selected areas.

                           c. Building shell shall meet ADA                c.   No requirement.
                              code requirements.

                           d. Roof:  A single ply membrane                 d.   No requirement.
                              insulated roof with R19 Rigid
                              Insulation.

Toilet Floors              a. Furnish and install ceramic tile             a.   No requirement.
                              on floor and full height wet walls.  Paint
                              and/or vinyl shall be used on remaining
                              walls.

                           b. Furnish and install stone                    b.   No requirement.
                              (granite or marble) vanity top with apron
                              and decorative mirrors.

                           c. Furnish and install ceiling                  c.   No requirement.
                              mounted baked enamel toilet partitions
                              with full height pilasters..

                           d. Furnish and install wall-mount,              d.   No requirement.
                              flush valve water closets and wall-hung
                              urinals to meet all code requirements.

                           d. Fully ADA compliant restrooms.               e.   No requirement.

Window Blinds              a. No window coverings are included             a.   Provide building standard blinds,
                              in the core & shell contract.                     1" aluminum horizontal blinds by Levalor,
                                                                                Riviera Delux with dust-guard and color
                                                                                to be determined.
</TABLE>

                                     D-12
<PAGE>

                             EXHIBIT D-2 TO LEASE
                             --------------------

                               Webb Interactive
                              The Neenan Company
                            Classic Schedule Layout

<TABLE>
<CAPTION>
Activity                                                                      Orig
--------                                                                      ----
ID            Activity Description                                            Dur      Early Start      Early Finish
--            --------------------                                            ---      -----------      ------------
<S>           <C>                                                             <C>      <C>              <C>
100           Initial Schematic Design                                         3         04OCT99          13OCT99
105           Review and Sign Off by Webb                                      0         15OCT99
110           Start Pricing Plans                                              5         22NOV99          29NOV99
120           Neenan Pricing                                                   6         30NOV99          07DEC99
115           Review & Sign Off Pricing Plan with Tenant                       4         07DEC99          10DEC99
125           Architectural Working Plans                                      8         10DEC99          21DEC99
195           Preconference Meeting with City                                  1         10DEC99          10DEC99
130           Backgrounds to engineers & Engineers drawings                    7         13DEC99          21DEC99
140           Print and Log into Building Department                           2         23DEC99          27DEC99
155           Building Department Review                                       35        23DEC99          27DEC99
135           Final Working Drawings Complete                                  1         22DEC99          22DEC99
145           Neenan Final Pricing                                             5         23DEC99          30DEC99
150           Fin.Review and Signoff Plans and Pricing by Webb                 4         27DEC99          30DEC99
165           Layout Wall                                                      3         28JAN99          01FEB99
170           Rough Mech and Fire                                              10        02FEB00          15FEB00
175           Frame Interior Walls                                             8         16FEB00          25FEB00
180           Finish Interiors                                                 45        28FEB00          28APR00
185           Tenant Move In                                                   3         01MAY00          03MAY00
</TABLE>

                                     D-13
<PAGE>

                              EXHIBIT E TO LEASE
                              ------------------

                             RULES AND REGULATIONS

     Landlord and Tenant agree that the following Rules and Regulations shall be
and hereby are made a part of this Lease, and Tenant agrees that Tenant's
employees and agents, or any others permitted by Tenant to occupy or enter the
Premises, will at all times abide by said Rules and Regulations:

     1.   The sidewalks, entries, passages, corridors, stairways and elevators
of the Building Complex shall not be obstructed by Tenant, or Tenant's agents or
employees, or used for any purpose other than ingress to and egress from the
Premises.

     2.   Furniture, equipment or supplies will be moved in or out of the
Building only upon the elevator designated by Landlord and then only during such
hours and in such manner as may be prescribed by Landlord and upon no less than
forty-eight (48) hours prior notice to Landlord. Landlord shall have the right
to approve or disapprove the movers or moving company employed by Tenant. Tenant
shall cause its movers to use only the loading facilities and elevator
designated by Landlord. In the event Tenant's movers damage the elevator or any
part of the Building Complex, Tenant shall forthwith pay to Landlord the amount
required to repair said damage.

     3.   No safe or articles, the weight of which may in the opinion of
Landlord constitute a hazard or damage to the Building or Building's equipment,
shall be moved into the Premises; provided, that Landlord acknowledges that
Tenant's general office furniture, equipment, files and portable safe, if any,
if approved as part of the initial Leasehold Improvements will not violate this
provision.

     4.   No sign, advertisement or notice shall be inscribed, painted or
affixed on any part of the inside or outside of the Building unless of such
color, size and style and in such place upon or in the Building, as shall be
first designated and approved in writing by Landlord, provided, however, there
shall be no obligation or duty on Landlord to allow any sign, advertisement or
notice to be inscribed, painted or affixed on any part of the inside or outside
of the Building except as otherwise provided in the Lease. No furniture shall be
placed in front of the Building or in any lobby or corridor, without the prior
written discretionary consent of Landlord. Landlord shall have the right to
remove all non-permitted signs and furniture, without notice to Tenant, and at
the expense of Tenant.

     5.   Tenant shall not do or permit anything to be done in the Premises, or
bring or keep anything therein which would in any way increase the rate of fire
insurance on the Building or on property kept therein, constitute a nuisance or
waste, or obstruct or interfere with the rights of other tenants, or in any way
injure or annoy them, or conflict with any of the rules or ordinance of the Fire
Department or of the Department of Health of the City and County where the
Building is located.

     6.   Tenant shall not employ any person or persons other than the janitor
of Landlord for the purpose of cleaning or taking care of the Premises, without
the prior written consent of Landlord. Landlord shall be in no way responsible
to Tenant for any loss of property from the Premises, however occurring, or for
any damage done to Tenant's furniture or equipment by the janitor or any of
janitor's staff, or by any other person or persons whomsoever; provided,
however, that the janitorial staff is bonded. The janitor of the Building may at
all times keep a pass key, and other agents of Landlord shall at all times be
allowed admittance to the Premises.

     7.   Water closets and other water fixtures shall not be used for any
purpose other than that for which the same are intended, and any damage
resulting to the same from misuse on the part of Tenant, Tenant's agents or
employees, shall be paid for by Tenant. No person shall waste water by tying
back or wedging the faucets or in any other manner.

     8.   Except for animals assisting disabled persons, no animals shall be
allowed in the offices, halls, corridors and elevators in the Building. No
person shall disturb the occupants of this or adjoining buildings or
<PAGE>

premises by the use of any radio, sound equipment or musical instrument or by
the making of loud or improper noises.

     9.   No vehicles, including bicycles, shall be permitted in the offices,
halls, corridors, and elevators in the Building nor shall any vehicles be
permitted to obstruct the sidewalks or entrances of the Building.

     10.  No additional lock or locks shall be placed by Tenant on any door in
the Building unless written consent of Landlord shall first have been obtained.
A reasonable number of keys to the toilet rooms if locked by Landlord will be
furnished by Landlord, and neither Tenant, Tenant's agents or employees shall
have any duplicate keys made. At the termination of this tenancy, Tenant shall
promptly return to Landlord all keys to offices, toilet rooms or vaults.

     11.  No window shades, blinds, screens, draperies or other window coverings
will be attached or detached by Tenant without Landlord's prior written consent.
Tenant agrees to abide by Landlord's rules with respect to maintaining uniform
curtains, draperies and/or linings at all windows and hallways.

     12.  No awnings shall be placed over any window by Tenant.

     13.  Tenant shall not install or operate any steam or gas engine or boiler,
or carry on any mechanical operation in the Premises. The use of oil, gas or
inflammable liquids for heating, lighting or any other purpose is expressly
prohibited. Explosives or other articles deemed extra hazardous shall not be
brought into the Building Complex.

     14.  Except as permitted by Landlord in conjunction with the initial
Leasehold Improvements, and except for normal office decorating, Tenant shall
not mark upon, paint signs upon, cut, drill into, drive nails or screws into, or
in any way deface the walls, ceilings, partitions or floors of the Premises or
of the Building, and any defacement, damage or injury caused by Tenant,
Tenants's agents or employees, shall be paid for by Tenant.

     15.  Tenant shall not obstruct or interfere with the rights of other
tenants of the Building, or of persons having business in the Building, or in
any way injure or annoy such tenants or persons.

     16.  Tenant shall not commit any act or permit anything in or about the
Building which shall or might subject Landlord to any liability or
responsibility for injury to any person or property by reason of any business or
operation being carried on in or about the Building or for any other reason.

     17.  Tenant shall not use the Building for lodging, sleeping, cooking
(other than customary cooking operations related to employee meals and catered
events for Tenant's business), or for any immoral or illegal purpose or for any
purpose that will damage the Building, or the reputation thereof, or for any
purposes other than those specified in the Lease.

     18.  Canvassing, soliciting, and peddling in the Building are prohibited,
and Tenant shall cooperate to prevent such activities.

     19.  Tenant shall not use the building for manufacturing or for the storage
of goods, wares or merchandise, except as such storage may be incidental to the
use of the Premises for general office purposes and except in such portions of
the Premises as may be specifically designated by Landlord for such storage.

     20.  Tenant shall not deposit any trash, refuse, cigarettes, or other
substances of any kind within or out of the Building except in the refuse
containers provided therefore. Tenant shall not introduce into the Building any
substance which might add an undue burden to the cleaning or maintenance of the
Premises of the Building. Tenant shall exercise its best efforts to keep the
sidewalks, entrances, passages, courts, lobby areas, garages or parking areas,
elevators, escalators, stairways, vestibules, public corridors and hall in and
about the Building clean and free from rubbish.
<PAGE>

     21.  Tenant shall use the Common Areas only as a means of ingress and
egress, and Tenant shall permit no loitering by any persons upon Common Areas or
elsewhere within the Building. The Common Areas and roof of the Building are not
for the use of the general public, and Landlord shall, in all cases, retain the
right to control or prevent access thereto by all persons whose presence in the
judgment of the Landlord, shall be prejudicial to the safety, character,
reputation or interests of the Building and its tenants. Tenant shall not enter
the mechanical rooms, air conditioning rooms, electrical closets, or similar
areas or go upon the roof of the Building without the express prior written
consent of Landlord.

     22.  Tenant shall cooperate with Landlord in obtaining maximum
effectiveness of the cooling system of the Building by closing drapes and other
window coverings when the sun's rays fall upon the windows of the Premises.
Tenant shall not obstruct, alter or in any way impair the efficient operation of
Landlord's heating, ventilating, air conditioning, electrical, fire, safety, or
lighting systems, nor shall Tenant tamper with or change the setting of any
thermostat or temperature control valves in the Building.

     23.  Subject to applicable fire or other safety regulations, all doors
opening into Common Area and all doors upon the perimeter of the Premises shall
be kept closed and, during nonbusiness hours, locked, except when in use for
ingress or egress. If Tenant uses the Premises after regular business hours or
on nonbusiness days, Tenant shall lock any entrance doors to the Building or to
the Premises used by Tenant immediately after using such doors.

     24.  Tenant shall not permit its employees or agents to smoke in any lobby,
hallway or restroom within the Building Complex or in any other areas of the
Building Complex posted as a non-smoking area.

     25.  Tenant shall not permit any employee, agent, or invitee to bring or
carry guns, weapons, firearms, or the like (including concealed weapons), into
the Premises or the Building Complex.