Yeah, this is the director who did The Exorcist.
It's Harold's birthday and Michael decides to throw a party for him with all their gay buddies. A 'straight' friend of Michael's shows up, however, and this creates a great amount of conflict, as he never knew his friend was gay. It's a pretty interesting and entertaining film. It's definitely a period piece, but very interesting to watch. It really gives you an idea of what gay folks had to deal with back in the late 60s and early 70s.
They showed this film alot at the Parkway since Clark and Diversey was boys town in Chicago back then.
It's one of the first films in the USA around a gay theme.