I found these videos of Frank Zappa on the Steve Allen Show. Zappa appeared on this episode in 1963, well before he became famous as a performer. Both Frank and Steve Allen use a bass bow to create aleatoric sounds on two bicycles, and they plus the studio band and audience perform along with some taped sounds.
Frank is beardless and very young on this episode, and I get a real kick out of his interactions with Steve Allen. The first video posted is actually the second part of the show, and this one features more playing:
This video features Frank and Steve doing a lot of talking, and the vibe between the two of them is pretty strange:
I found these videos (I had always heard of this Zappa appearance on the Steve Allen Show) while poking around on WFMU’s Beware of the Blog. There is a post up there featuring an interview with John Cage from 1960. Check it out here.