Jam session at the Athletic Field across the street from the festival
lostlivedead: May-June 1967 Grateful Dead Itinerary Overview (comment) As per Rock Scully, "We set up a stage and, after the shows, the various bands would put on jam sessions. Jimi Hendrix, Eric Burdon, Jerry Garcia, Phil Lesh, the Airplane... We all took acid together and played all night."