Summer `69, a new "Musical Happening" which began performances June 24, officially opens July 15 at off-off-Broadway's Theatre 80. It had originally been set to close July 11, but recently extended at the theatre until Aug. 8.

Writer Bill Van Horn told Playbill On-Line that the show must vacate the theatre after Aug. 8 and is currently looking to transfer to another Off Broadway theatre. Among the possibilities is the Westside Theatre. The Westside's current resident, The Mystery of Irma Vep, closes on July 18.

Actor-writer-director Bill Van Horn and Ellen Michelmore co-wrote '69, a look at the summer of Woodstock, told through tunes by Bob Dylan, Arlo Guthrie, Jerry Garcia and Robert Hunter, Janis Joplin, Country Joe McDonald, J. R. Robinson and Stephen Sills and Graham Nash. Seven actors play over 30 roles, ranging from a farmer and his wife to suburban parents and their hippie children to Captain Condom. Former Tommy Tune collaborator and Barrymore Award winner Bruce Lumpkin directs.

Lumpkin collaborated with Tune on My One and Only, Nine and Grand Hotel, co-directing the West End production. Other credits include Cabaret for which he won a Philadelphia Barrymore Award for Best Director and Best Musical. Lumpkin is currently developing a musical version of the film Time After Time and Honky Tonk Angel, the Patsy Cline story.

The cast includes Alyssa Claar (30th anniversary production ofHair), Jamie Hurley, Brian Maillard , Ron McClary, Kirk McGee (Uncle Vanya), Anne Moore, Rik Sansone and Christine M. Williamson. The design team is John Farrell (set), James Tomaselli (sound), Colleen McMillan (costumes) and Jeffrey Koger (lighting). Michelmore is the musical director.

Tickets ($12) are available by calling Ticketmaster at (212) 307-4111. Theatre 80 is located at 80 St. Marks Place.

-- By Christine Ehren