Letterman announced Thursday that he was retiring, and would be stepping away from the desk he made famous in 2015 (watch the full announcement). In honor of his 21 years at CBS, and 32 years in late night, let's look back at some of his most unforgettable Late Show moments. (Remember: There is no off position on the genius switch.
1993: Madonna flirts
Dave's 1994 interview with Madonna got off to a weird start before the Material GIrl even appeared, and skewed more awkward from there, with Madonna cursing up a storm and Dave badgering her about her interest in the NBA. It was like being stuck in a bar at closing time with two friends you really hoped would not hook up.
1994: Johnny Carson sits at the desk one last time
Johnny Carson didn't say a word, but still stole the show.
1995: Drew Barrymore flashes
Before her late-'90s comeback, Barrymore was in the midst of her wild-child phase when she jumped up on Dave's desk and gave him a split-second flash as a birthday present. "Unflappable" is never a word you'd use to describe Letterman, but Drew had him more flustered than ever.
2001: Dave returns after 9/11
911 David lettermans reflection on by Yakwild
Along with Jon Stewart's return to The Daily Show, Dave's post-tragedy monologue represented a small step back from the brink.
2005: Oprah ends the feud
Reports vary on how Dave and Oprah's decades-long fight began. Was it over his disastrous Oscars gag, or a skipped restaurant check? Either way, it ended in 2005, when Oprah showed up on Dave's couch for the first time in 16 years to promote the Broadway version of The Color Purple.
2006: Michael Richards apologizes
It's never a comfortable experience when an actor goes on a talk show to apologize for using racial slurs, but Michael Richards made the moment even more stilted than it had to be when he made his obligatory mea culpa via satellite.
2008: McCain cancels, Dave fumes
Late-night television isn't the cultural force it once was, but still, it's never a good idea to tick off a talk-show host in the waning moments of a presidential campaign.
2009: Joaquin Phoenix goes catatonic
That Phoenix's bizarre appearance was later revealed to be a piece of avant-garde performance art takes a bit of the fun out of this moment, but that doesn't detract from the bite of Letterman's closing barb: "Joaquin, I'm sorry you couldn't be here tonight."
2009: Dave confesses
It sounds like the setup for a gag: Someone had incriminating evidence against Letterman, and they were using it to blackmail him. Instead, over the course of an excruciating 10-minute segment, Dave revealed that yes, he really was being extorted, and yes, it really was because he had had an affair – with a staffer, no less.