Jerry Seinfeld is set to temporarily take over as co-host of Live! after Regis Philbin's final show on Friday. Hey, when did Seinfeld and Philbin get so close, anyway? And why is Philbin on the cover of Newsweek with him instead of with longtime friend David Letterman? That's what a jealous Letterman wanted to know when he asked Seinfeld about his relationship with Reeg on tonight's Late Show.

Elisabeth Hasselbeck had quite a bone to pick with Bill Maher on The View this morning about a joke he'd told about her months ago, and pick it she did. One would think he'd mind being attacked, but on tonight's Late Show, Maher told David Letterman he was actually pleased with how she reacted: "Thank you, Elisabeth Hasselbeck, for making me look good!"

Justin Timberlake has never been shy about his penchant for pot. In a recent interview, JT said that marijuana helps him to "stop thinking" and "some people are just better high."

Salma Hayek has kept a relatively low profile since having a child with (and eventually marrying) French billionaire Francois-Henri Pinault, so she had lots to discuss with David Letterman when she stopped by tonight's Late Show to promote her new film. Here are highlights of their lively chat, including her struggle to quit smoking, her four-year-old daughter's adult-like attitude, and Letterman's obsession with Hayek's earrings.

Tracy Morgan got into some hot water back in June for saying during a stand-up show that he'd stab his son to death if he were gay. Morgan apologized more than once for his remarks in the weeks that followed. But he didn't exactly help his case during an interview on tonight's Late Show.

George Clooney returned to the Late Show tonight after a three-and-a-half year absence, so naturally there were many things David Letterman wished to discuss with him. Chief among them: Vera Farmiga's backside, which apparently has been on Letterman's mind since seeing Clooney and Farmiga appear together in Up in the Air a couple of years ago.

Well, this was uncomfortable. On tonight's Late Show, David Letterman interviewed '80s movie star-turned-alcoholic flameout Sean Young. The chat was bizarre from the onset—Young described disciplining her teenage sons with a horsewhip—and then turned downright sad as Young pleaded for work with anyone who'd consider hiring her. The saddest part? The video clip that Young shared of her dressed up in a Catwoman suit, screaming "I'm not crazy!" to random passers-by.

While many TV newsmen aren't good at anything else, a one-trick pony Brian Williams is not—and he's got a reel full of everything from cameos on 30 Rock to slow jams with Jimmy Fallon to prove it. The NBC Nightly News anchor does best, though, when there's no agenda or script, which is why his appearances with David Letterman on the Late Show are often so memorable.

Anderson Cooper probably woke up this morning thinking he'd only be on two television shows by the end of the day. But then the opportunity came along to appear on a third program—and promote his new daytime talk show in the process—and he couldn't resist.

In addition to being a possible Republican presidential candidate, New Jersey Gov. Chris Christie is really fat. So naturally, in recent days Christie's been the butt of jokes made by everyone from Chris Matthews to David Letterman, who on tonight's Late Show delivered a top 10 list of "ways the country would be different if Chris Christie were president." Here's a clip of the segment.

Modern Family star Sofia Vergara stopped by the Late Show on Thursday to gloat to David Letterman about her show's big night at the Emmys. And while I suspect any conversation between Letterman and Vergara would be entertaining, this one was made even better by the fact that they kept confusing each other throughout it.

On the eve of its premiere, X Factor judge Paula Abdul—aka the human incarnation of a lost dog finally seeing its owner again—wandered onto Tuesday night's Late Show, where she was asked by David Letterman to explain the differences between The X Factor and American Idol. She, uh, tried.

The cast of Two and a Half Men appeared on tonight's Late Show to present David Letterman's Top 10 list of reasons to still tune in. But as you'll see in this video, Ashton Kutcher sort of seems over it already, so... points at least for being self-aware?

Sarah Jessica Parker visited tonight's Late Show to chat with David Letterman and promote her new film, I Don't Know What She's Talking About. Oh wait, that's not the title of her movie, it's my reaction to the interview. Because what the hell?

Silly you, thinking yesterday's Keeping Up with the Kardashians season finale marked the beginning of a reprieve from America's most undeservedly famous family. Because tonight, Kim, Kourtney and Khloe took the Late Show by storm for an interview with David Letterman. They were annoying, obviously, but you know what was kind of fun? Watching Letterman conduct the interview like he was talking to three surprisingly articulate toddlers with gigantic breasts. Here's our highlight reel.

Newly minted Dancing with the Stars contestant David Arquette was on tonight's Late Show. Arquette talked to David Letterman about being sober from alcohol, reconciling with estranged wife Courteney Cox, being enamored with fellow DWTS contestant Rob Kardashian's "great ass" (it's true, his ass is pretty spectacular), being scared of Nancy Grace, and more. But mostly, he just giggled. A lot! Check out our video of the interview's best four minutes above.

The last time Regis Philbin had anything to do with a David Letterman Top 10 list, he was ruining it. But not this time. On tonight's Late Show, Letterman used the segment to wish Philbin a happy 80th—and to speculate as to how the octogenarian spent his big day. Video of Letterman's tribute is above.

Ashton Kutcher stepped out of his insanely oversized trailer on the Two and a Half Men set tonight for long enough to visit the Late Show. And while most of us aren't the least bit interested in knowing about Kutcher's Charlie Sheen-replacing character—or the details of Sheen's on-screen death—David Letterman nonetheless seemed quite intent on getting him to cough up some details. Video of the interrogation is above.

Before Californians started mocking people on the East Coast for having the nerve to react to the earthquake that struck near DC on Tuesday, people on the East Coast actually were reacting to it. But what were they saying? On tonight's Late Show, David Letterman gave us his Top 10 guesses.

David Letterman returned to the Late Show on Monday, his first broadcast since word got out that a jihadist had marked him for death and demanded his tongue be cut out over a nonsensical joke about Sarah Palin.