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                                                                    EXHIBIT 10.2

$21,292,550.00                                                     JULY 23, 2002


                               EXCHANGE DEBENTURE

     1.   For value received, Nextera Enterprises, Inc., a Delaware corporation
("Borrower"), promises to pay to the order of Knowledge Universe, Inc., a
Delaware corporation, or its assigns ("Lender"), the principal sum of Twenty-One
Million Two Hundred Ninety-Two Thousand Five Hundred Fifty Dollars
($21,292,550.00) (the "Principal Amount"). Interest shall accrue from the date
hereof on the outstanding principal at ten percent (10%) per annum, compounded
quarterly, based on the calendar year, but in no case shall the interest rate
exceed the maximum rate allowed by law.

     2.   The Maturity Obligations shall be due and payable on January 2, 2004
(the "Maturity Date"). As used herein, "Maturity Obligations" shall mean the
entire outstanding principal amount, together with all accrued but unpaid
interest thereon, and all other sums due and unpaid hereunder.

     3.   The Maturity Obligations shall be secured by all of Borrower's assets
and all of Borrower's subsidiaries' assets pursuant to that certain Guarantee
and Security Agreement of even date herewith between Lender, Borrower, and
Borrower's subsidiaries which are a party thereto.

     4.   This Exchange Debenture and the payment of any portion of the Maturity
Obligations is and shall be expressly subordinated and junior in right of
payment to the prior payment in full of: (i) all obligations owed by Borrower to
Fleet National Bank for itself and the other lenders under the Amended And
Restated Credit Agreement dated March 29, 2002; (ii) all obligations owed to
Knowledge Universe Capital Co. LLC pursuant to the debenture dated January 5,
1998 evidencing indebtedness in the original principal amount of $24,970,000
(with a current balance of approximately $12,809,094); and (iii) all obligations
owed to Knowledge Universe Capital Co. LLC pursuant to the debenture dated
December 15, 2000 evidencing indebtedness in the original principal amount of
$10,000,000 (with a current balance of approximately $11,601,200).

     5.   All payments due under this Exchange Debenture are payable in lawful
money of the United States of America at Lender's office at 844 Moraga Drive,
Los Angeles, California 90049 or at such other place as Lender or other holder
hereof shall notify Borrower in writing.

     6.   All payments received by Lender on this Exchange Debenture shall be
applied by Lender as follows: first, to the payment of accrued and unpaid
interest; and second, to the reduction of the principal amount.

     7.   Any portion of the principal amount, or interest unpaid at maturity,
or when the entire amount of this Exchange Debenture is otherwise due and
payable, shall thereafter accrue interest at a rate of fifteen percent (15%) per
annum (the "Delinquency Rate"). The Delinquency Rate shall be effective both
before and after any judgment as may be rendered in a court of competent
jurisdiction provided, however, that if such Delinquency Rate is deemed to be
interest in excess of the amount permitted to be charged to Borrowers under
applicable law, Lender shall be entitled to collect a Delinquency Rate only at
the highest rate permitted by law, and any interest actually collected by Lender
in excess of such lawful amount shall be deemed a payment in reduction of the
principal amount then outstanding under this Exchange Debenture and shall be so
applied.

     8.   Borrower may prepay this Exchange Debenture in whole or in part
without any premium or penalty.

     9.   In the event this Exchange Debenture is turned over to an attorney at
law for collection after default, in addition to the Maturity Obligations,
Lender shall be entitled to collect all costs of collection, including but not
limited to reasonable attorneys' fees incurred, whether or not suit on this
Exchange Debenture is filed, and all such costs and expenses shall be payable on
demand.

     10.  This Exchange Debenture may not be changed orally, but only by an
agreement in writing signed by the party against whom such agreement is sought
to be enforced.

     11.  Borrower, for itself and its successors and assigns, and each endorser
or guarantor of this Exchange Debenture, for its heirs, successors, and assigns,
hereby waives presentment, protest, demand, diligence, notice of dishonor and of
nonpayment, and waives and renounces all rights to the benefits of any statute
of


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limitations and any moratorium, appraisement, and exemption now provided or
which may hereafter be provided by any federal or state statute, including
but not limited to exemptions provided by or allowed under the Bankruptcy
Reform Act of 1978, both as to itself and as to all of its property,
whether real or personal, against the enforcement and collection of the
obligations evidenced by this Exchange Debenture and any and all
extensions, renewals, and modifications hereof.

     12.  It is the intention of the parties to conform strictly to applicable
usury laws from time to time in force, and all agreements between Borrower and
Lender, whether now existing or hereafter arising and whether oral or written,
are hereby expressly limited so that in no contingency or event whatsoever shall
the amount paid or agreed to be paid to Lender or the holder hereof, or
collected by Lender or such holder, for the use, forbearance, or detention of
the money to be lent hereunder or otherwise, exceed the maximum amount
permissible under applicable usury laws. If under any circumstances whatsoever
fulfillment of any provision hereof at the time performance of such provision
shall be due, shall involve transcending the limit of validity prescribed by
law, then ipso facto, the obligation to be fulfilled shall be reduced to the
limit of such validity; and if under any circumstances Lender or other holder
hereof shall ever receive an amount deemed interest, by applicable law, which
would exceed the highest lawful rate, such amount that would be excessive
interest under applicable usury laws shall be applied to the reduction of the
principal amount owing hereunder and not to the payment of interest, or if such
excessive interest exceeds the unpaid principal amount and other indebtedness,
the excess shall be deemed to have been a payment made by mistake and shall be
refunded to Borrower or to any other person making such payment on Borrower's
behalf. The terms and provisions of this paragraph shall control and supersede
every other provision of all agreements between Lender and Borrower and any
endorser or guarantor of this Exchange Debenture.

     13.  This Exchange Debenture shall be governed by and construed under the
laws of the State of California. Borrower hereby submits to personal
jurisdiction within the State of California for the enforcement of Borrower's
obligations hereunder, and waives any and all personal rights under the law of
any other state to object to jurisdiction within the State of California for the
purposes of litigation to enforce such obligation of Borrower.

     IN WITNESS WHEREOF, Borrower, intending to be legally bound hereby, has
caused this Exchange Debenture to be duly executed.

                               "BORROWER"

                               Nextera Enterprises, Inc., a Delaware corporation

                               By: /s/ Michael Muldowney
                                   --------------------------------------------
                                   Michael Muldowney
                                   Its Chief Financial Officer

     THIS INSTRUMENT IS SUBJECT TO THE SUBORDINATION AGREEMENT DATED AS OF JULY
23, 2002, AS FROM TIME TO TIME IN EFFECT, AMONG THE MAKER, THE PAYEE, AND FLEET
NATIONAL BANK, AS AGENT, WHICH, AMONG OTHER THINGS, SUBORDINATES THE OBLIGATIONS
OF THE OBLIGOR HEREUNDER TO THE PRIOR PAYMENT OF CERTAIN OBLIGATIONS OF THE
OBLIGOR TO THE HOLDERS OF SENIOR INDEBTEDNESS AS DEFINED THEREIN.

THIS INSTRUMENT IS SUBJECT TO THE SUBORDINATION AGREEMENT DATED AS OF JULY 23,
2002, AS FROM TIME TO TIME IN EFFECT, AMONG THE MAKER, THE PAYEE, AND KNOWLEDGE
UNIVERSE CAPITAL CO. LLC, WHICH, AMONG OTHER THINGS, SUBORDINATES THE
OBLIGATIONS OF THE OBLIGOR HEREUNDER TO THE PRIOR PAYMENT OF CERTAIN OBLIGATIONS
OF THE OBLIGOR TO KNOWLEDGE UNIVERSE CAPITAL CO. LLC AS PROVIDED THEREIN.