I saw them at the Teen Center on Victory Blvd in the SF Valley for 50 cents in 1968 before they became popular. It was back when they put colored water and vegetable oil on glass plates and then used an overhead projector to project the moving images on the walls. Psychedelic was born.
My brother took it to another level by learning the drum solo, turning the lights off in a room, lighting 2 cigarettes and then playing along with the song with the "drumsticks" held over his head. You only saw the glowing cigarette tips in perfect time and thought you were watching King Kong play. LOL