Fifty years ago, on 21-January-1966, the tribes gathered at San Francisco's Longshoreman's Hall for the Trips Festival. I don't remember this, but I do remember later events in Golden Gate Park, which we could hear from our back yard.
Years later I read Tom Wolfe's The Electric Kool-Aid Acid Test. I better understood many things I had heard about when I was a kid, about Ken Kesey, Stewart Brand and the Merry Pranksters. The Festival went on for three days. The Grateful Dead and Big Brother and the Holding Company performed.