The Acid Tests were a series of parties held by Ken Kesey in the San Francisco Bay Area during the mid 1960s, centered entirely around the use of, experimentation with, and advocacy of, the psychedelic drug LSD, also known as "acid."
The name "Acid Test" was coined by Kesey, after the term "acid test" used by gold miners in the 1850s. He began throwing parties at his farm at La Honda, California.[1] He took the parties to public places, and advertised with posters that read, "CAN YOU PASS THE ACID TEST?", and the name was later popularized in Tom Wolfe's 1968 book, The Electric Kool-Aid Acid Test. Musical performances by the Grateful Dead were commonplace, along with black lights, strobe lights, and fluorescent paint. 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.