Four sitcoms - two returning and two premiering - start new seasons between tonight and Sunday. The news: In a TV environment that has seen a handful of decent comedies in the last 10 years, they're all funny.

All four focus on outsiders, offering similar appeal to their audiences in a fragmented world, with special resonance to people under 30, a generation that has grown up with no clear center. All the series feature characters - some desperate, some lacking the awareness to sense their desperation - searching for something better.

Family is minimal in these shows. Where it appears, it's completely broken, whether it's Curb Your Enthusiasm's Larry David trying to dump his live-in girlfriend before her cancer diagnosis (so he won't look like a total heel), which happens Sunday, or Mac bedding his friends' mother, which happened in season two of It's Always Sunny in Philadelphia.

Sunny starts its fifth season at 10 tonight on FX, and Community, about a band of misfits at a community college, premieres at 9:30 on NBC.

Curb returns for its seventh season on HBO at 9 p.m. Sunday, followed at 9:30 by the new Bored to Death, about an author with permanent writer's block seeking excitement. Drawing hope from hundreds of noir mysteries, he starts a second life as an unlicensed private eye.

This season's Curb centers on making a reunion episode of the ultimate outsider sitcom, Seinfeld. Purportedly about nothing, Seinfeld was a satire on a culture in which people can, almost mysteriously, make their way in physical comfort with absolutely no emotional connections.

Jerry, George, Elaine, and Kramer used the other 5,999,999,996 people in the world only to try to achieve their selfish goals.

The characters in Curb Your Enthusiasm, the majority skewed fictional versions of Hollywood insiders played by themselves, would seem to have achieved the American dream: wealth and comfort and a certain degree of fame.

But the emptiness of their lives is appalling, and, as it was with Seinfeld, intensely funny. Almost anybody has more social skill than this crew, and the loneliest real-life loser is more emotionally advanced than star Larry David's TV version of himself.

The reunion show is doomed to dissolve in a soup of petty arguments, so don't get your hopes up for it. Do anticipate the joy of seeing Jerry Seinfeld, George Costanza, Julia Louis-Dreyfus, and Michael Richards back together having fun. They show up in episode three.

On Sunday, comedy ensues in the more usual Curb Your Enthusiasm manner after Larry's (married) buddy Jeff sleeps with the sister - freshly released from a mental asylum - of his other buddy, Bob "Super Dave" Einstein.

Evolving into a cult hit, Sunny moves Seinfeld over to the dark side of cable. Four slackers and the debauched father of two of them, played with hilarious gusto by Danny DeVito, will do anything, except work, to make money or get the upper hand in a situation.

Comics have been doing this sort of thing on TV since I Love Lucy and The Jackie Gleason Show in the '50s, but never with the hilarious depravity of Sunny. Tonight, a little kid tells one of the gang, "Dude, eat my boogers," as Frank tries to work the foreclosure crisis to his benefit and Sweet Dee seeks to improve her cash flow by offering to carry twins as a surrogate mother.

"If it's a matter of price," she tells Muffy and Skip in their lovely Montgomery County backyard, "I'm willing to cut you a deal on the second one."

Curb and Sunny (and Seinfeld) operate on the same principle as a lot of reality shows. We outsiders all can laugh at people who are clearly less skilled at making it through life than we are.

Bored to Death and Community offer a slightly different experience, a little wistfully. Their psyches may be broken, but they still have hearts, and you will root for them, not mock them. Community even expresses in its title something glaringly missing from so many Americans' life. You'll find it here, Community promises.

Community stars The Soup's Joel McHale as an ex-lawyer who found that his gift of gab outweighed any need for a law degree. He tries to get next to twentysomething dropout Britta (endearingly attractive relative newcomer Gillian Jacobs) by falsely telling her he's organizing a Spanish study group.

The group includes Chevy Chase as an old tycoon trying to keep active, a lovable Palestinian American with Asperger's syndrome, and a few other classics, including a no-nonsense divorcee played by Yvette Nicole Brown.

Ken Jeong plays the Spanish professor, Mr. Chang, the kind of quiet joke in the topsy-turvy world that characterizes this sweetly funny show.

In Bored to Death, quirky Jason Schwartzman plays the quirky alter ego of quirky author Jonathan Ames, adrift in the anomie of New York City with a comic-book artist (Hangover's Zach Galifianakis) as the only friend he can (sort of) rely on.

Ted Danson, a very nice and down-to-earth man who has made himself a giant among clueless comedic characters with huge egos, completes an outsider double here. He recurs as a skewed version of himself on Curb, and on Bored to Death, he's a pot-addled cross between Seinfeld's Mr. Peterman and Donald Trump.

What a pleasure to find some humor in a culture that makes that guy a hero.

Contact television critic Jonathan Storm at 215-854-5618 or jstorm@phillynews.com.