Psychedelic film The Acid Tests were a series of parties held by author Ken Kesey primarily in the San Francisco Bay Area during the mid-1960s, centered on the use of and advocacy for the psychedelic drug LSD, commonly known as "acid".

Kesey took the parties to public places, and advertised with posters that read, "Can you pass the acid test?

The Acid Tests are notable for their influence on the LSD-based counterculture of the San Francisco area and subsequent transition from the beat generation to the hippie movement.

Prior to Babbs' creation, it was discovered that particular music usually sounded distorted when cranked to high levels because of the cement floor on the San Francisco Longshoreman's Union Hall (where the Trips Festival was taking place).

[35] On Saturday January 22, the Grateful Dead and Big Brother and the Holding Company came on stage, and 6,000 people arrived to drink punch spiked with LSD and to witness one of the first fully developed light shows of the era.