On Saturday, May 1 from 2pm-4pm, Richie Unterberger will show rare film clips by San Francisco Bay Area folk-rock and psychedelic rock performers from the mid-1960s through the early 1970s in Koret Auditorium, in the basement of the main branch of the San Francisco Public Library at 100 Larkin Street. Included will be footage by Jefferson Airplane, Big Brother & the Holding Company with Janis Joplin, Santana, Moby Grape, Country Joe & the Fish, Sly & the Family Stone, Creedence Clearwater Revival, the Grateful Dead, the Beau Brummels, and the Youngbloods. Admission is free.