Set in the backyard of a middle class South Philadelphia neighborhood early in the summer of 1973, the comedy-drama focuses on the 21st birthday celebration of Harvard student and Maria Callas fan Francis Geminiani. In attendance are his divorced blue collar father Fran and Fran's widowed girlfriend Lucille, next-door neighbor Bunny Weinberger and her overweight son Herschel, and Francis' classmates, the wealthy WASP Hastings siblings Judith (who seeks romance with Francis) and Randy (the object of Francis' unexpressed affection), who have arrived unexpectedly, much to their friend's dismay. All are dysfunctional to varying degrees, and the interactions among them provide the play with its comic and dramatic moments.
Playwrights Horizons first staged the play in December 1976 with a cast that included Jonathan Hadary, Jon Polito, and Sigourney Weaver. The following March it was mounted by the Circle Repertory Company with Hadary, Danny Aiello, Carol Potter, and Robert Picardo. Critical response encouraged the producers to transfer the play uptown.
The Broadway production, with the same cast directed by Peter Mark Schifter and supervised by Marshall W. Mason, opened on May 21 1977 at the Little Theatre, where it ran for 1,819 performances. The play was nominated for the Drama Desk Award for Outstanding New American Play.
The 1980 screen adaptation, written and directed by Richard Benner, was entitled Happy Birthday, Gemini. The cast included Madeline Kahn, Rita Moreno, Alan Rosenberg, David Marshall Grant, and Sarah Holcomb.
A 1999 off-Broadway Second Stage Theatre revival closed after 14 performances.