"After a short address by Prabhupada, Ginsberg sang "Hare Krishna" to the accompaniment of sitar, tambura, and drums, requesting the audience to "[j]ust sink into the sound vibration, and think of peace."[6] Then Prabhupada stood up and led the audience in dancing and singing,
as the Grateful Dead, Big Brother and the Holding Company, and Moby Grape joined the chanting and accompanied the mantra with their musical instruments.[39][40][41] The audience eagerly responded, playing their own instruments and dancing in circles. The group chanting continued for almost two hours, and concluded with the swami's prayers in Sanskrit while the audience bowed down on the floor. After Prabhupada left, Janis Joplin took the stage, backed by Big Brother and the Holding Company, and continued the event with the songs "The House of the Rising Sun" and "Ball and Chain" late into the night.[6][42] " -
http://en.wikipedia.org/wiki/Mantra-Rock_Dance
COME ON! how can there not be SOME recording of this anywhere?!?!