One of the band’s earliest major performances in 1967 was the Mantra-Rock Dance—a musical event held on January 29, 1967, at the Avalon Ballroom by the San Francisco Hare Krishna temple. Big Brother and Janis Joplin performed there along with Hare Krishna founder Bhaktivedanta Swami, Allen Ginsberg, Moby Grape, and Grateful Dead, donating proceeds to the Krishna temple.
Link: https://en.wikipedia.org/wiki/Big_Brother_and_the_Holding_Company