David Letterman's most controversial moments

David Letterman has taped his final episode of the 'Late Show,' ending a successful, indelible 33-year run on late-night television. As with many long careers in show business, Letterman's was filled with as many highs as lows. In fact, the Ed Sullivan Theater, which hosted the 'Late Show' for decades, was often the setting for some of the most talked about and controversial television moments in modern-day history. We've pulled together nine times the 'Late Show' truly made our jaws drop. Check them out, below.

The Extortion Plot

Arguably the most shocking moment in 'Late Show' history came on October 1, 2009, when Letterman revealed to his audience, live on camera, that he had been the target of a $2 million extortion plot over allegations that he had slept with female members of his staff. Letterman was brutally candid in his nearly 10-minute confession — "My response to that is, yes I have," he said — marking a sharp contrast to his notoriously private persona. Millions of viewers were subsequently left feeling shocked, confused, and, quite frankly, a little icky. Letterman later reflected on the incident in an April 2015 interview with The New York Times, saying, "Looking at it now, yes, I think [CBS] would have had good reason to fire me." Still, he stood by his decision to air his dirty laundry on television. "I didn't know what else to do. I couldn't think of a really good lie."

The O'Reilly Battle

Letterman has never been one to shy away from a controversial interview, as proven by his heated exchange of words with Fox News host Bill O'Reilly on January 3, 2006. As many others were doing at the time, Letterman and O'Reilly got into a pretty rough argument over the ongoing War in Iraq. (You can guess who was on which side.) The debate eventually grew so heated, Letterman couldn't stop himself getting in a few jabs at the infamous talking head. Among his choice insults: "You're putting words in my mouth, just the way you put artificial facts in your head"; and "I have the feeling about 60 percent of what you say is crap." Of course, as so often happens in Hollywood, the two patched things up — at least long enough for O'Reilly to make one final visit in March 2015. Naturally, they got into it again.

When John McCain Suspended His Interview

If there's one lesson to be learned from Letterman's decades-long stint as host of the 'Late Show,' it's this: never, ever cancel an appearance. Senator John McCain had to learn that the hard way when he abruptly canceled a scheduled interview during the peak of his Presidential campaign in 2008. His excuse: He was suspending his campaign to focus on the growing financial crisis. Letterman, of course, didn't buy it. He proceeded to spend nine-plus minutes ripping McCain to shreds, all of which reached an epic boiling point when McCain was caught getting mic-ed up for an interview with then-host of the CBS Evening News, Katie Couric. Months later, McCain finally made an appearance on the 'Late Show,' during which he jokingly confessed, "I screwed up." Judging by the 2008 election results, we can't say he was wrong.

Madonna's 14 F-Bombs

Of all the interviews Letterman conducted on the 'Late Show,' his March 31, 1994 chat with Madonna remains his most controversial. The interview itself got off to a rough start before it even began; during Madonna's intro, Letterman joked that she had "slept with some of the biggest names in the entertainment industry." Naturally, Madonna wasn't exactly comfortable when she finally made it onto the stage. And yet, even Letterman seemed shocked by what happened from there. Amid awkward conversations and passive-aggressive jabs, the Grammy-winning music icon managed to drop the F-bomb not once, but 14 times, leading to one of the most censored episodes in late-night history. But hey, at least the ratings were great.

Drew Barrymore's Flashing

Former child star Drew Barrymore proved her days of being That Adorable Girl from 'E.T.' were long gone during a 1995 interview in which she jumped onto Letterman's desk and flashed her chest. While the rest of us struggled to react to what had just happened, Letterman calmed everyone down with a simple joke, saying, "I can't thank you enough for that."

When Farrah Fawcett Reached Cloud, Um, Something

Who the hell knows what happened before Farrah Fawcett entered the Ed Sullivan Theater for her interview with Letterman in 1997. All we know is that, when the cameras started rolling, things got super weird. The late 'Charlie's Angels' star appeared to be under the influence of, um, something as she stammered her way through the infamously awkward interview, to the point where even Letterman couldn't hold his laugh. Given her death 12 years later, the interview now feels sad, if not depressing. At the time, it was just plain bizarre.

The Grilling Of Paris Hilton

Paris Hilton appeared on the 'Late Show' in 2007 to promote, oh, it doesn't matter. In fact, all Letterman seemed to care about was Hilton's stint in jail for violating her probation. After a minute or so of awkward conversation, Letterman cut right to the chase, asking Hilton, "How'd you like being in jail?" What followed were eight minutes of painfully awkward television — so awkward that we almost felt sorry for Hilton. Almost, anyway.

When Joaquin Phoenix Pranked Us All

Joaquin Phoenix had everyone wondering if he had just committed career suicide after a shockingly strange interview he gave to Letterman in February 2009. The Oscar-nominated actor donned a long beard, sunglasses, and a genuinely strange attitude as he struggled to get through the nine-minute interview. In fact, things went so bad, Letterman said he finally owed Farrah Fawcett an apology. Yowch. Of course, as everyone well knows now, Phoenix's interview was really just a stunt for his mockumentary, 'I'm Still Here.' Still, the interview remains a defining moment in 'Late Show' history.

The Michael Richards Racist Rant Apology

Following a video obtained by TMZ, in which 'Seinfeld' icon Michael Richards was seen hurling racial slurs at an audience member at a stand-up performance, Richards made an appearance on Letterman via satellite to formally apologize. The moment was arranged by the guest that evening, Jerry Seinfeld, who had the good intentions of helping his former co-star clear the air. Unfortunately, the apology turned awkward, to the point where even Richards questioned whether the 'Late Show' was the right place to apologize. Sadly, he was probably right.