Exhibit 3.157

                                                                          PAGE 1

                                State of Delaware

                        Office of the Secretary of State

                        --------------------------------

      I, EDWARD J. FREEL, SECRETARY OF STATE OF THE STATE OF DELAWARE, DO HEREBY
CERTIFY THE ATTACHED IS A TRUE AND CORRECT COPY OF THE CERTIFICATE OF
INCORPORATION OF "PRIMEDIA VENTURES, INC." FILED IN THIS OFFICE ON THE
THIRTEENTH DAY OF APRIL, A.D. 1998, AT 4.30 O'CLOCK P.M.

      A FILED COPY OF THIS CERTIFICATE HAS BEEN FORWARDED TO THE NEW CASTLE
COUNTY RECORDER OF DEEDS.

                                     [SEAL]


                            [SEAL]   /s/ Edward J. Freel                
                                     -----------------------------------
                                     Edward J. Freel, Secretary of State

2889214   8100                       AUTHENTICATION:   9051806

981160924                                      DATE:   04-29-98


                          CERTIFICATE OF INCORPORATION
                                       OF
                             PRIMEDIA VENTURES, INC.

      The undersigned, in order to form a corporation for the purpose
hereinafter stated, under and pursuant to the provisions of the Delaware General
Corporation Law, hereby certifies that:

      FIRST: The name of the Corporation is PRIMEDIA Ventures, Inc.

      SECOND: The registered office and registered agent of the Corporation is
The Corporation Trust Company, 1209 Orange Street, Wilmington, New Castle
County, Delaware, 19801.

      THIRD: The purpose of the Corporation is to engage in any lawful act or
activity for which corporations may be organized under the General Corporation
Law of Delaware.

      FOURTH: The total number of shares of stock that the Corporation is
authorized to issue is 1,000 shares of Common Stock, par value $0.01 each.

      FIFTH: The name and address of the incorporator is Beverly C. Chell, 745
Fifth Avenue, New York, NY 10151.

      SIXTH: The Board of Directors of the Corporation, acting by majority vote,
may alter, amend or repeal the By-Laws of the Corporation.

      SEVENTH: Except as otherwise provided by the Delaware General Corporation
Law as the same exists or may hereafter be amended, no director of the
Corporation shall be personally liable to the Corporation or its stockholders
for monetary damages for breach of fiduciary duty as a director. Any repeal or
modification of this Article SEVENTH by the stockholders of the Corporation
shall not adversely affect any right or protection of a director of the
Corporation existing at the time of such repeal or modification.

      IN WITNESS WHEREOF, the undersigned has signed this Certificate of
Incorporation on April 2, 1998.


                                        /s/ Beverly C. Chell         
                                        -------------------------    
                                        Beverly C. Chell