On this week's episode of "It's Always Sunny in Philadelphia," Kaitlin Olson finally gets to stop hiding her belly behind big shirts, towels and such. Thank God. Although it probably hasn't been too difficult for her to conceal her condition. She's the skinniest pregnant chick I've ever seen.

The rest of the Sunny gang certainly hasn't noticed Sweet Dee's motherly glow. When they rag on her for eating too much and getting fat, she fires back: "I'm pregnant." The ever-observant Mac whines, "I feel like you say that all the time now," before reiterating that he doesn't care about her or what's happening with her body. None of them care until Dee drops the bomb—one of them is the father.

Since Dee will only say that one of the guys knocked her up at last year's Halloween party, they have to try to piece together the events of that hazy night, when most of them were "browned out." You might call this "The Hangover II: This Time It's Actually Funny."

Flashing back to the party, we see that Dee is supposed to be a "sexy angel," but she wore wings around the wrong crowd. The guys steadily chip away at her self-esteem with a barrage of bird jokes, then turn around and drool over another bird, a girl dressed as a "sexy peacock." In a great sight gag, and one of the funniest moments of the entire series, Dee's costume continues to evolve into something more bird-like, until she finally appears to Mac in the men's room as a giant, squawking ostrich.

Each of the guys takes a turn trying to remember how the party went down, which only confuses things more. Charlie is convinced that he made out with the Waitress after punching out her new boyfriend, but it turns out that he actually made out with Artemis, who was trying to make Frank jealous. And despite the fact that Artemis "doesn't remember most evenings," she recalls overhearing Mac and Dee having sex in the bathroom, which forces Mac to admit that he was really in there with Margaret McPoyle. The only thing everyone knows for sure is that Mac screwed over Dennis by bailing on their Mario and Luigi costume plan by showing up with a "sexier look...that dude from Lord of the Rings, Veejo Morgenstein." Without his "brother," Dennis just kind of looked like a thinner, creepier Ron Jeremy, which kind of makes sense. Frank was dressed as Spider-Man (er, excuse me, Man-Spider), while Charlie wore a Phantom of the Opera costume, thinking that he was a vampire who probably eats theater people.

Eventually, the guys decide that they should probably ask the McPoyles (who Charlie may or may not have a truce with) what happened, since they were soberly chugging milk all night long. The McPoyles explain that Dee was so desperate to prove that she was sexy, that she forced Peacock Girl to switch costumes with her and then dragged the most easily manipulated member of the gang, Charlie, into the back room for some banging. Of course, since Dennis had already revealed earlier that he remembered having sex with Peacock Girl after he switched costumes with Charlie, what I had been cringing in anticipation of all episode long finally came out. As Dennis realized that he must have banged Dee, he reacted as any brother would—vomitously.

When the boys race back to Dee's apartment (with Frank leading the way, barking about flushing out the demon spawn) to discuss their predicament, Dee is amused that this mystery has been eating away at them all day. Turns out, she only told those boners that one of them was the dad so they'd pay attention to her. Dennis, Mac and Charlie are all off the hook. And just like that, they go back to not caring about Dee, her body or her little unborn baby bird.

Grade: A-

Random Thoughts:

- I'm not sure which was funnier: 1) The guys sincerely believing that Mac had just coined the phrase "brown out," or 2) Mac's self-satisfied expression after he said it, as he waited for everyone to tell him how awesome it was.

- I really wanna know what Artemis does with a rolled up hamburger bun during sex. It doesn't hurt to learn a few new tricks.

- While I loved Liam McPoyle's angry outburst, demanding that Mac call his sister (now that he's had his way with her), I don't see what the point would be. I mean, she's a deaf mute.

- I hope we find out soon who Dee's baby daddy is. My money is on Cricket or Bill Ponderosa. It would be cool though if it turned out to be the character played by Jason Sudeikis, who will be guest-starring next week. Anything to get him back on the show.