By Mandi Bierly
Updated September 13, 2007 at 11:12 PM EDT
Credit: Lewis Jacobs/NBC

A strange thing happened last week, after I told a few coworkers I was going to chat with Charlie Day (Charlie) and Glenn Howerton (Dennis) from It’s Always Sunny in Philadelphia — which returns tonight at 10 p.m. for Season 3 on FX. I found out I wasn’t the only one who loves this show.

Here, 10 reasons why you should to be tuning in — and buying Seasons 1 and 2 on DVD, out now. (Fans, back me up in the comments section.)

1. The show is just wrong… All you need to know about “the gang” who owns Paddy’s Irish bar in Philadelphia — Dennis, Charlie, Mac (Rob McElhenney), Dee (Kaitlin Olson), and Frank (Danny DeVito) — is that they’re always thinking of themselves. They attend an abortion rally or pretend to be crippled to get dates; they’re upset when they hear former classmates were molested by their old gym teacher and they weren’t. In tonight’s season premiere, they find a “Dumpster Baby,” which Mac and Dee name “D.B.” and try to make a child star. When an agent tells them white babies aren’t “selling,” they try to get it a tan so it looks Latino. Dennis also gets inspired by the film An Inconvenient Truth to better the world, yet, as Day says, “In typical, It’s Always Sunny fashion, he ends up doing the complete opposite.” (Pictured, from left to right, Howerton, McElhenney, Olson, DeVito, and Day)

2. They need you to tell them when they get it right. “It’s hard when you live with the jokes as long as we do,” Day says. “We start writing episodes, and by the time we’re done editing them, almost a year has gone by. It’s tough to trust them and know they’ll be funny.” The Season 2 episode “The Gang Gives Back,” when Mac, Dee, and Dennis coach children’s basketball teams, is an example of something they weren’t sure would work. Now it’s one of fans’ — and their own — favorites. The spoof “Hundred Dollar Baby,” where Dee and Charlie get hooked on “performance enhancing supplements,” nearly didn’t make it off the page.

3. Dennis will be shirtless a lot this season. “We were counting the other day, it’s like eight episodes,” Howerton says. “There’s something very funny to me about someone who has so much vanity and constantly thinks that he can solve any dilemma by just poppin’ his shirt off.” Don’t miss the upcoming episode “The Gang Gets Held Hostage,” in which Dennis, Charlie, Mac, and Dee are held captive in Paddy’s by the incestuous McPoyle clan. Dennis, dressed only in tighty whities, tries to seduce the deaf and dumb sister to earn his freedom.

addCredit(“It’s Always Sunny in Philadelphia: Everett Collection”)

4. According to Day, DeVito is doing “some of his funniest acting since Throw Momma From the Train.” DeVito, who’d been a fan of the show before he joined the castfull-time last season, returns for all 15 new episodes. “We wrote lastseason before we’d ever met him. We just rented a lot of movies, andwatched episodes of Taxi,” Day says. “This year, we knew himreally well, so we have certain episodes where he’s got the best jokes.Wait till you see Danny DeVito in a skintight purple Juicy Jumpsuit.”Or, crawling around in the ventilation system at Paddy’s, like JohnMcClane, in the hostage episode.

5. Stephen Collins is back. Yes, the dad on 7th Heaven has guested on thisshow before — as Dennis and Dee’s do-gooder father (all their lives,they’d thought it was DeVito’s Frank) — and he’ll return for theupcoming episode “Dennis and Dee’s Mom is Dead.” When their motherleaves all their money to Collins’ character, Dee and Frank pretendthey’re engaged so he’ll gift her some of it. You’ll definitely cringe(in a good way) when an on-to-them Collins asks to see Dee and Frank(now called “Seamus”) at their most intimate. “So perhaps now would bea good time for you to pleasure yourself for him. Then eventuallySeamus will mount you,” he tells Dee, while sitting in a chair at thefoot of her bed. So how did they get Collins on the show in the firstplace? Day was in the Williamstown Theatre Festival with Collins in thelate ’90s, and thought he’d be perfect for the role. “We had to sendhim over some episodes and write him a letter,” Day says. “To just lethim know that we couldn’t pay him,” Howerton adds.

6. Charlie’s “indetermined amount of illiteracy” — always funny. “To have a character that is clearly illiterate, but who’s in complete denial of it — you don’t usually see that,” Howerton says. Luckily, you’ll be seeing it play into a few more Sunny story lines this year.

7. This photo. It’s from an upcoming episode where Sweet Dee dates a local Eminem-style rapper.
Day: We suspect him to be possibly, mildly mentally retarded. But she says he’s just from the streets, so he talks funny. He’s a very successful rapper, so we figure if he can do it —
Howerton: [Lowers voice] If a retarded guy can have a successful music career—
Day: And as usual, the joke’s on us that we can’t do it at all. We are the ones who are retarded. You know, I don’t mean to make light of that, but um—
Howerton: [Laughs] But I do.
Day: But I do. [Sighs] It also makes me sad. But we start a band. It starts out me and Mac and Frank, and we won’t let Dennis be in the band even though he’s the best singer, because he’s too into the ’70s glam rock thing. So we start a more punk rock style band called Chemical Toilet, and I write a song called “Night Man,” which I say is about the spirit of the Night Man, who comes into my room at night and fills me up, and that when he comes inside me, I become the Night Man. Mac seems to think that those lyrics mean something else, so he kicks me out of the band, and Dennis talks me into the glam rock. We get ourselves a cheap Casio and we perform “Day Man.” Fighter of the Night man.
Howerton: Champion of the Sun.
Day: Master of karate and friendship.

8. They’re willing to bribe you… If you’re a Nielsen household, that is. “You can write this down,” Day says. “If you own a Nielsen box, and mail FX proof that you programmed it to our show every time it aired, I will mail you…” Howerton suggests $1,000. Then, $10. Day momentarily considers $.05, before deciding on “an autographed photo of the cast. Or at least, me. I can’t speak for DeVito, but you’ll definitely get me.”

9. But they shouldn’t have to. See the clip below from Season 2’s “Dennis and Dee Go on Welfare.” They’re buying crack so that they can get a blood test that will prove that they are addicts and eligible for government assistance.

10. We wish these guys success. Especially Day, who met McElhenney when they were flown from New York to L.A. to test for a pilot— that got axed while they were in the air. “It was the second time in a row that happened to me,” he says.

Who’s with us?