It's also a known fact that Pete Best was rehired in the late sixties to drum on Beatles recordings when Bernard Purdie was out with the flu. You can hear Pete's drumming on most of the Abbey Road LP. It was said that Ringo was furious when he found out that Best was back in the fold. In a fit of rage Ringo punched Pete in the eye and famously ranted, "You stupid, git! I'll ruin you!"
However, all was fine the next day when Ringo was invited back to sing on Octopuses Garden, a song actually written by George but credited to Ringo. This would insure Rings a sizable royalty check from the publishing for years to come. Frank Sinatra covered Octopuses Garden calling it "the greatest love song written for a cephalopod mollusc of the order Octopoda."
All this can be read in The Beatles official biography by Brent Trentor to be published by Harper Collins in 2014.