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                                                                   EXHIBIT 10.20

$300,000                                                  Minneapolis, Minnesota
                                                               December 13, 1996

                          SUPPLEMENTAL REVOLVING NOTE

         FOR VALUE RECEIVED, each of the undersigned, hereby jointly and
severally promises to pay to the order of BNC NATIONAL BANK (the "Bank") in the
lawful money of the United States at its offices at 200 Metropolitan Centre,
333 South Seventh Street, Minneapolis, MN 55402, or at such other place as the
Bank may from time to time designate:

         (i)     the principal sum of Three Hundred Thousand and 00/100
                 ($300,000) Dollars, or such other principal amount as may be
                 owing to Bank for the repayment of loans made pursuant to the
                 Supplemental Revolving Credit Commitment as set forth in that
                 certain Loan Agreement dated June 20, 1996, between Bank and
                 the undersigned as the same may be amended from time to time
                 (the "Loan Agreement"), which sum shall be due and payable in
                 full on April 11, 1997; and plus

         (ii)    interest on the unpaid principal amount of this Note from time
                 to time outstanding payable in arrears at a rate of interest
                 equal to the Reference Rate (as defined in the Loan Agreement)
                 plus two percent (2.0%) per annum (calculated on the basis of
                 the number of days actually elapsed in a 360-day year) on the
                 last day of each calendar month commencing with the first
                 month following the date hereof.  Following the occurrence of
                 an Event of Default as defined in the Loan Agreement, the
                 principal indebtedness shall bear interest at a floating rate
                 of two percent (2%) per annum greater than the otherwise
                 applicable rate.

         This Note is the "Supplemental Revolving Note" referred to in the Loan
Agreement and is subject to all of the agreements, terms and conditions therein
contained which are incorporated herein by reference.  In no event shall
interest hereunder be in excess of the maximum interest rate permitted by law.

         This Note has been delivered in the State of Minnesota and shall be
construed and enforced in accordance with the substantive laws of such state.

         Each of the undersigned and all guarantors expressly waive any
presentment, demand, protest, notice of protest, and notice of dishonor.
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         This Note has been executed by each of the undersigned as co-makers
and not as a surety, accommodation marker or guarantor, and each of the
undersigned hereby expressly waive all claims and defenses, if any, as a
surety, accommodation maker and/or guarantor.

                                  CONCORDE GAMING CORPORATION, a 
                                  Colorado corporation
                                  
                                  
                                  By                              
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                                           Its                    
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                                  CONCORDE GAMING OF SOUTH DAKOTA, 
                                  INC., a South Dakota corporation
                                  
                                  By                              
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                                           Its                    
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Witness:
                                           
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