Ringo vs. Letterman
Ringo Starr made a memorable solo appearance at Sunset one night, arriving so intoxicated that Mike Binder, who was working the door, had to help him to a seat in the back. Starr was seated just as David Letterman took the stage, and the former Beatle immediately began heckling him, which attracted the attention of every comic within earshot. Letterman had a reputation for eviscerating hecklers, and as word spread along the back hallway, other comics started filling into the room to witness the impending bloodshed.
It wasn’t a fair fight. In the spotlight, Letterman couldn’t see who the heckler was, so he showed no mercy, and Starr was too drunk to appreciate how badly Letterman was beating him up. Finally, one of the comics took pity and called out, “Hey, Dave, it’s Ringo.”
"Oh, that makes sense," Letterman shot back in the direction of Starr. "You ruined your career, and now you’ve come here to ruin mine."
-From “I’m Dying Up Here: Heartbreak and High Times in Comedy’s Golden Era”