Turn on, tune in, drop out

"Turn on, tune in, drop out" is a counterculture-era phrase popularized by Timothy Leary in 1966. In 1967, Leary spoke at the Human Be-In, a gathering of 30,000 hippies in Golden Gate Park in San Francisco and phrased the famous words, "Turn on, tune in, drop out".

Source: Wikipedia — Turn on, tune in, drop out (CC BY-SA 4.0)