Politics and Hollywood mingle on a cordial basis most days of the year. But on the night of the White House Correspondents' Association Dinner, the gloves come off. On Saturday night, both President Barack Obama and comedian Conan O'Brien took to the dais at the "nerd prom" -- and each took a very different approach to making the room laugh ... and blush.

Here are some of the most memorable moments:

Winning!
President Obama kicked things off in high style by heading up to the microphone to the strains of DJ Khaled's rap song"All I Do Is Win." "How do you like my new entrance music?" he asked the crowd, putting on a little 'tude. "Rush Limbaugh warned you about this. Second term, baby."

'Obama,' the movie
President Obama played up his Hollywood connections with the help of Steven Spielberg. The President told the crowd that the "Lincoln" director's next project would be another presidential biopic: "Obama." "Why wait?" said the director (who was also in the audience) in a taped video piece about his follow-up to the Oscar-winning "Lincoln." And since "Lincoln's" star Daniel Day-Lewis went over so well, he was going to cast Lewis in the key role. Cut to President Obama pretending to be Daniel Day-Lewis pretending to be President Obama. "The hardest part? Trying to understand his motivations," said Obama-as-Lewis-as-Obama. Another interesting "casting" choice: "30 Rock's" Tracy Morgan as Vice President Joe Biden. We'd watch that.

That's entertainment
The president showed he clearly has his finger on the pulse of all kinds of entertainment, referring to Jimmy Fallon's upcoming "Tonight Show" ascension and the recent kerfuffle over Beyonce and Jay-Z's trip to Cuba ("I've got 99 problems and now Jay-Z's one"). He also noted that no one from The History Channel was in attendance: "I guess they were embarrassed by the whole 'Obama is a devil' thing," he said, referring to the appearance of Satan in History's "The Bible" miniseries, and how the actor who played him seemed to resemble the president. 

Zing!
Conan O'Brien used his 15 minutes to zap his way through as many topics as possible, with as many one- or two-line zingers as he could manage:

• "Since (Obama's) being elected, the number of Popes has doubled, and the number of 'Tonight Show' hosts has tripled!"
• After noting that members of the cast of "Duck Dynasty" were in the audience: "That means the guys from 'Storage Wars' said 'no.'"
• And he wrapped up by proposing another made-for-TV movie -- this time a miniseries -- starring many um, familiar faces playing the president's team and colleagues. Suggestions? Vice President Joe Biden played by Bob Barker, Rep. Paul Ryan played by Mr. Bean (a character created by Rowan Atkinson) and Sen. Harry Reid "played by the old man from the 'American Gothic' painting.'" We still think Morgan's the better choice for Biden, though.

Kudos for Beantown
Casting the inevitable Obama administration movie aside, the one area the two speakers did overlap on and grow serious about was the way in which the citizens of Boston have shown their strength in adversity following the Boston Marathon bombings on April 15. Boston native O'Brien noted he had relatives in nearby Watertown, and he thanked the president for his support of the city. "It's been said recently that you don't mess with Boston," said O'Brien. "As someone who grew up there, I'd like to echo that sentiment. It's really pretty simple: If you're going to pick on a city, don't choose one where nine out of every 10 people are related to a cop."

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Conan O'Brien won't be performing at the White House Correspondents' Association Dinner until Saturday night, but he's already in the nation's capital, goofing around -- as shown in this photo he tweeted Friday.

"Practicing my opening 'Goofy Sunglasses' bit," he noted in the pic's caption.

This will be Conan's second time on the Dinner dais, having performed there originally in 1995, when President Clinton was in office. He told Politico that having the leader of the free world at his elbow was actually helpful: "Clinton was really laughing and he gets really red in the face when he laughs, and at one point he was hitting the table and I thought, 'This is great!' ... I definitely wouldn’t want to do my show every night with the president of the United States sitting next to me, chewing Nicorette. But it certainly amps things up."

The White House Correspondents' Dinner will be shown on several networks on Saturday night and O'Brien is expected to appear at 10 p.m. ET. Check back on TODAY.com for a roundup of the funniest moments!

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Wednesday's announcement that Jay Leno would be stepping down from "The Tonight Show" hosting duties on NBC to make room for "Late Night's" Jimmy Fallon in Spring 2014 clearly had the staffs of every late night show scrambling to rewrite their opening monologues -- because everyone had something to say!

First, there was the back-patting; this transition is being done with an air of friendliness that did not necessarily characterize the one that brought Conan O'Brien into "Tonight's" seat for a few months in 2009.

"He is a hell of a guy!" said Leno last night to his audience about Fallon. "He's going to do a great job. I just have one request for Jimmy: We've all fought, kicked and scratched to get this network up to fifth place. Now we have to keep it there! Jimmy, don't let it slip into sixth! We are counting on you."

Over at "Late Night," Fallon acknowledged that his shift was the big news of the day: "Hello! Welcome!" he began. "This is 'Late Night With Jimmy Fallon' -- for now," he said. "You guys probably heard the news -- I’m going to be taking over 'The Tonight Show' next February! But don't worry. Until February, our focus is right here on whatever this show is called."

Added Fallon, "I want to thank everyone here at 'Late Night,' the staff, the crew and, of course, The Roots. I have to say thanks to Jay Leno for being so gracious. It means so much to me to have his support. I just want to thank the fans for staying up to 12:35 a.m. and watching us." 

Over on the other networks, former "Late Night" host David Letterman played up the story for laughs on CBS' "Late Show." Letterman was notoriously angered not to have been offered the "Tonight" show gig himself in 1992 when Leno was tapped, and that feud hasn't faded over the last 22 years. 

"I got a call from my mom today," said Letterman, who also devoted his Top 10 list to Leno. "She says, 'Well, David, I see you didn't get 'The Tonight Show' again."

Leno wasn't about to let it go unsaid, either, quipping, "Folks, I got to be honest with you, I had a really awkward day today," he said in the opening. "I had to call David Letterman and tell him he didn't get 'The Tonight Show' again. Awful! Terrible!"

The Hollywood Reporter noted that Letterman also referenced the O'Brien issue, questioning not Fallon but the choice to make another switch: "Didn’t we just go through this?" he said. "Jay Leno now is being replaced, and this is the second time this has happened. I mean, it’s crazy. He’s being replaced by a younger late-night talk show host -- what could possibly go wrong? Honestly. They had pretty good luck with this in the past."

Speaking of O'Brien, he also addressed the topic around the 30-minute mark of his TBS show "Conan." "I want to congratulate Jimmy. That is a really fun gig." His audience laughed, and he followed up: "You laugh, he said, but it really is. Jimmy is the perfect guy to do it. ... He's going to do a fantastic job. So congratulations, Jimmy."

The one broadcast late night host who doesn't have any dog in this race, Jimmy Kimmel, also had something to say. 

"It is a big one for the world of late-night television," said Kimmel in his "Jimmy Kimmel Live!" monologue on ABC, according to The Hollywood Reporter. "As you probably heard -- it was announced officially today -- that, starting in February of next year -- after the Olympics -- I will take over as new host of 'The Tonight Show.' I spoke to Jay on the phone today." A member of his staff interrupted. "Excuse me for one moment. ... OK. Um, apparently it was a different Jimmy."

He read one of the headlines about the changeup on his cell phone and added, "Turns out I will not be hosting 'The Tonight Show.' Does anyone know what the return policy is on yachts?"

In the end, though, it was largely friendly banter and Fallon's ascension to the throne (which will move, along with the show, to New York City), seems to have gone over well. But Leno had one last warning: "NBC says in five years, they plan to replace Jimmy with Justin Bieber," he said. "They are moving too quickly!"

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Jason Kempin / Getty Images

Comedian Conan O'Brien is set to host the White House Correspondents Dinner.

Team CoCo is headed to Washington. Conan O'Brien has signed on to emcee the annual White House Correspondents Dinner set for April 27 and airing on C-SPAN. 

This will be the second go-round in the gig for the late night host -- he last performed the duties at the 1995 affair featuring then-President Bill Clinton. 

The news was first announced on Twitter by the organization's president, Ed Henry, Fox News' chief White House reporter. 

President Obama and Jimmy Kimmel high-five at the White House Correspondents Dinner 

"@ConanObrien was terrific at '95 correspondents dinner w/Clinton - excited about @TeamCoco return engagement April 27 @andyrichter," Henry tweeted. 

No doubt, Conan will have plenty of material to work with considering who's coming. 

Along with a who's who of journalists and celebrity guests (we're lookin' at you, Kim Kardashian and Donald Trump), President Barack Obama and first lady Michelle Obama, per tradition, will be in attendance as the guests of honor. 

Take a look back at the 2012 White House Correspondents Dinner 

Previous comics who've hosted the event include Jimmy Kimmel, Seth Meyers, Jay Leno and, perhaps most memorably, Stephen Colbert, whose infamous roast of President George W. Bush caused quite the kerfuffle.

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Election night was not a good evening for "The Colbert Report's" Stephen Colbert, who showed up Wednesday night face-down on his desk, wearing his red (natch) bathrobe, tossing around popcorn and cracking open a beer. It was a far cry from the crowd dancing he did following the first presidential debate.

“What are you people doing here? Shouldn’t you be out celebrating?” he asked his audience. “Because evidently you don’t listen to anything I say!”

But things went as well as could be expected for "The Daily Show's" Jon Stewart, who saw President Obama re-elected and the Democrats pick up a couple of seats in the Senate.

But if there was one downside, it was that his live show that evening prevented him from watching how the folks at Fox News handled themselves watching their nightmare come true. Still, Stewart did riff on how the network he calls “Bulls--- Mountain” spent the night and its aftermath, and it was worth waiting for.

Unsurprisingly, he showed clips of Karl Rove’s desperate attempts to un-call Ohio for Obama, and Fox anchor Megyn Kelly’s challenge to Rove, “Is this just math that you view as a Republican to make yourself feel better, or is this real?”

“Did you see this? Did you record this? Did you TiVo it? Because you can play it back and forth like I did today,” Stewart said. “Here’s what happened. I just want to get it straight Karl, very quickly. Are you lying to yourself? Or to the millions of viewers? Because you’re lying.”

And Stewart found Kelly’s comment notable in another way, suggesting to the network’s executives that "'Math you do as a Republican to make yourself feel better' is a much better slogan for Fox than what they have now.”

Stewart also examined what happened in the hours after the election, when the Fox News team looked at the shattered remains of their election map and attempted to make some sense of what happened.

First came the predictable excuse that many voters, clearly more than the 47 percent Mitt Romney dismissed in that infamous campaign-event-turned-viral-video, took advantage of the chance to line their pockets at the expense of the selfless, wealthy job-creating class.

“What an incredible story to tell yourselves. ‘We would have won, if not for the moral failings of the non-real Americans,’” Stewart said. “Last night minorities, who feel entitled to things, came away and took the country away from the self-sufficient white Medicare retirees and upper class tax avoidance experts, or as they’re also known, ‘your audience.’”

Fox also blamed negative campaigning from Obama, and the smearing of Romney’s record. Of course, much of the attacks were originally made by Romney’s rivals in the primary, causing Stewart to note, “This election wasn’t murder. It was auto un-erotic asphyxiation.”

Finally, the network tried to treat the results as something less than a mandate, a confusing approach given the lopsided nature of the electoral college results, particularly if Florida is called for Obama once the results are finally tabulated.

 “Yes, let this resounding victory by Barack Obama be a lesson to the president. If you don’t moderate your positions, you may not win that third term!” Stewart said.

Nate Silver, the man of the hour in the data-driven community, was Stewart’s guest on Wednesday’s “Daily Show.” Silver came under fire from the right when his "FiveThirtyEight" blog predicted an overwhelming likelihood of an Obama victory at a time when the conventional narrative was that this election would be “razor tight,” whatever that means.

Considering the results went almost exactly as his analysis predicted, however, a lot of those critics owe Silver an apology.

“Don’t you want to stand up and go ‘I am Nate Silver! Bow down to me! I am Nate Silver, Lord and God of the Algorithm?” Stewart asked.

Silver demurred, perhaps because his blog wasn’t perfect. It did call that North Dakota senate race wrong.

Meanwhile, over on the broadcast networks, David Letterman noted during his "Late Show" monologue, "Well, it's over. And as usual, the guy from Kenya won." Jay Leno on "The Tonight Show" congratulated President Obama on his re-election, and noted there was hope for the GOP since depression "is covered by Obamacare."

And "Late Night's" Jimmy Fallon (whose dog is not apparently to be trusted with predicting presidential race winners) trotted out his Romney character one more time, chatting on the phone with "President Obama," who noted that he had done well with the Latino vote. "Which is odd, because 80 percent of Latinos work for me," said Fallon/Romney.

"I'm just going to focus on the good times," said Romney/Fallon. "Remember that first debate?"

"Obama" replied: "Yep. You remember ... right now? Ha! Burn notice!"

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