The Beatles release Revolver

Revolver is the seventh album by The Beatles, released on 5 August 1966. Many of the tracks on Revolver are marked by an electric guitar-rock sound, in contrast with their previous, folk rock inspired Rubber Soul. It reached #1 on both the UK chart and U.S. chart and stayed at the top spot for seven weeks and six weeks, respectively.

It was released before the Beatles' last tour in August 1966, but they did not perform songs from the album live. Their reasoning for this was that many of the tracks on the album, for example "Tomorrow Never Knows", were too complex to perform with live instruments

http://en.wikipedia.org/wiki/Revolver_(album)