John McCain and David Letterman

After weeks of derision from David Letterman, John McCain finally took the Late Show stage Thursday to face the music — and did so in front of the talker's biggest television audience in nearly three years.

Once the senator made his entrance — mock-fear on his face and jokes flying about flak jackets — Letterman wasted no time in getting to the point. "So what exactly happened?" he asked. "I got to think maybe I'm just not important enough."

"I screwed up," McCain said. "But look at all the conversation I gave you."

"I'm willing to put this behind us," Letterman told him.

The gentlemen's face-to-face was watched by 6.53 million viewers, Late Show's largest audience since Dec. 1, 2005 (when Dave's other "frenemy," Oprah Winfrey, dropped by to swap olive branches).

After the aforementioned exchange, a notably humble and relieved McCain let out a big sigh and repeated, "Thank you, thank you, thank you, thank you very much!" Of course, this being Letterman, it wasn't that easy: The host asked for Gov. Sarah Palin as a guest and a cushy white House gig.

Letterman and McCain have had tension between them since September, when the senator missed an appearance on the show, citing his trip to Washington for economic talks. During the missed broadcast, though, he was seen being interviewed by Katie Couric, just a few blocks from Letterman's studio. The snub has since been the source of endless fodder for the comedian, who has taken shot after shot at the presidential hopeful for blowing him off.

McCain's on-air repentance may have been much-anticipated, but his wasn't the only political appearance on Thursday's late-night lineup. Joe Biden made a surprise visit to Jay Leno's Tonight Show to introduce the evening's broadcast. Joking with Leno about his propensity for verbal gaffes, he promised not to flub the opening…with humorous results. (Check out the video here to see how he handled it).

With only three weeks left until the election, the candidates are already doing us all a public service: Letting us laugh in tough times — even at their own expense. How do you think the hosts and candidates handled themselves?