Awesome Music: "Aquarius"; "Hair"; "Walking In Space"; "Let The Sunshine In". The whole score, really.
Best Known for the Fanservice: The famous nude scene lasts for merely twenty seconds and is so dimly lit that one critic quipped, "I couldn't even tell if any of them were Jewish". Yet it's the most talked-about scene in the show, leaving people who haven't seen it with the impression that the ENTIRE show takes place with the actors naked.
Breakaway Pop Hit and Covered Up: The show produced four popular singles— the title song by The Cowsills, "Starshine" by Oliver, "Aquarius" by the 5th Dimension, and "Easy To Be Hard" by Three Dog Night.
Genius Bonus: The opening vocal line of the song Sodomy is the titluar word sung on an upward arpeggio of the 5th scale degree, a root, and a 3rd. Or, in solfege, sol-do-mi...
Ho Yay: Deliberately written into the show itself, which provides quite some subtext between Claude and Berger at times. In some productions, Claude and Berger actually make out throughout the show (but usually in the context of polyamorous moments with Sheila.)
Supporting character Woof: "I'm not a homosexual or anything, but I would make love to this man" (Mick Jagger). Bordering on Transparent Closet. Lampshaded by Jeanie, who points out that Woof is 'hung up on' Claude.
Also a Les Yay: In "White Boys," the last appealing trait of white boys listed is that they're "Beautiful like girls." (Note this is being sung by black girls.)
Tear Jerker: If "The Flesh Failures" can't make you tear up, nothing will.
Unintentional Period Piece: Was considered modern when it premiered in 1968, and now is one of the most iconic pieces of 60s cultural history.
Adaptation Displacement: The film was made in 1979 after the hippie movement was considered to be over, synth music was king, and Reagan was about to be elected. As such it was felt to be anachronistic at the time since it felt like a product of the early '70s, and didn't make too great an effort to "upgrade" the message of the movie, and only slightly "disco-ized" the original soundtrack. This is fortunate for the film's rewatchability, however, today, since the musical's original message and milieu can still be considered relevant today whereas Disco is Dead. At the time of the release, however, it was viewed as hopelessly retro.