I have to believe these guys had a lot of fun with this.
This is Earl Scruggs playing his banjo with his sons Randy on acoustic guitar and Gary on harmonica, Steve Martin on banjo, Vince Gill and Albert Lee on electric guitar, Marty Stewart on mandolin, Glen Duncan on fiddle, Jerry Douglas on dobro, Glenn Wolf on bass, Harry Stinson on drums, Leon Russell on organ and Paul Shaffer on piano in a November 15, 2001 appearance on the David Letterman show.