It's official: I'm a jackass

So, I'd heard that Letterman would be doing his tribute to Johnny Carson last night.But when I turned it on, the monologue seemed old, so I figured the show must be a rerun and turned it off.

Well, it turns out those old jokes were what amounted to Carson's last monologue.

David Letterman paid tribute to Carson, who died January 23, by delivering a "Late Show" monologue Monday composed entirely of jokes the retired "Tonight" show host had quietly sent him in his final months.

Only after the monologue was through and Letterman was back behind his desk did he tell the audience who had written the jokes.