Arnold Weinstein, author of Red Eye of Love, was something of a mentor of mine at Columbia. (Learned a lot of bad habits from him.) He was involved, I think, in a musical version of Red Eye of Love, so add him to the list we were making the other day.
I'm not old enough to have seen many of the off-Broadway plays of the sixties in the sixties. My father produced one, and I think I saw it, called The Infantry. In the cast were two long-haired kids named Jimmy Rado and Gerry Ragni and they showed my father a draft of a musical they'd written. It seemed not to have a plot, so my father passed. On Hair
Off-Broadway I enjoyed Streamers quite a bit, and of course Sister Mary Ignatius Explains It All For You. I once saw a production of Endgame (from the 60's, by Beckett) that featured the most fascinating stage effect I've ever seen. The set, at rise, was entirely draped; then, there's some noise (like the sound of a nuclear holocaust) and, with great force and speed, all the drapes got pulled out through a hole in the rear wall. The director of this production went on to direct many a Broadway play, including premieres by Albee and Miller, I think. And yes, I'm also fond of The Zoo Story, which I saw directed by Albee himself. (It didn't use a real switchblade.)