The Shining (1980)
That evening, when people tuned in for the Tonight Show, it did not start off with the normal theme song and visuals, but for no apparent reason there was an immediate cut from the normal "coming up next" bumper to a film sequence. There was Jack Nicholson running with an axe, Shelley Duvall screaming, the axe going through the door, then Nicholson saying his famous Johnny Carson line, at which time the Tonight Show theme played and the show started. It was one of the funniest moments in the history of television. It also drove another couple of million people to see the movie, giving it an unexpected extended run.