They say living is easy and comedy hard, but Judd Apatow knows enough about both to make comedy about the difficulty of living look like a cinch. A prolific producer of knockabout comedies pillorying the lunacies of the sports (Talladega Nights: The Ballad of Ricky Bobby) and entertainment industries (Anchorman: The Legend of Ron Burgundy, The TV Set), Apatow turned writer-director and shifted his loopy gaze to material that’s as familiar as an old boot — coming of age, work, love and marriage — giving it a personal stamp that’s filthy-minded, sweet-tempered and fresh as a daisy. Sexual terror was his subject in The 40-Year-Old Virgin; his new movie, Knocked Up, is about the fear of growing up. Both draw their vitality from being set among the freaks and geeks who have shaped Apatow’s life and become his bread and butter.

Lord knows, the world doesn’t lack for slacker movies, but Apatow’s singular achievement has been to drag an increasingly worn-out indie subgenre into the mainstream without sacrificing its R-rated edge. He’s also a cockeyed, foulmouthed romantic who brings together unlikely partners and makes them stick against formidable odds. In The 40-Year-Old Virgin, worldly Catherine Keener saved fastidious Steve Carell from his obsessive loneliness and the less-than-subtle efforts of the single guys he works with to part him from his cherry. In Knocked Up, opposites of a different stripe attract, and it’s harder to decide who is saving whom.

Breakfasting awkwardly together after a boozy one-night stand, Alison (Grey’s Anatomy star Katherine Heigl) and Ben (Seth Rogen) come face to face with how little they have in common other than the fact that they’re perfect strangers. She’s an ambitious reporter for a leading entertainment-news television network. He’s a shambling, chronically underemployed Jewish Build-a-Bear with a painfully acute understanding of just how far out of his league he’s strayed with this lithe, blond shiksa. So when Alison calls Ben several weeks later, he’s thrilled, at least until she drops the bombshell that she’s pregnant. “Oh, fuck off,” he blurts out, which is less a rejection than an Apatow slacker’s preferred way of registering shock. On one level, Knocked Up is a nerd’s wet dream: Against her better judgment, Alison grows fond of her accidental beau, though it’s hard to imagine anyone less qualified to do the right thing in such a predicament than Ben, who’s so strapped for cash and romantic imagination that he proposes by bringing her an empty engagement-ring box. Still, he squares his chubby shoulders and does his best to shape up. When Ben and Alison have to step into each other’s world, their troubles really begin.

Like most of the other comedians Apatow has worked with — Ben Stiller, Will Ferrell, Adam Sandler, Carell — Rogen, a Canadian standup comic who all but stole the show as the potty-mouthed floor salesman in The 40-Year-Old Virgin, combines hapless sweetness with a stubborn sense of adolescent self that refuses to cave to the demands of adulthood. Egged on by the four like-minded bozos with whom he lives in a disheveled state of arrested development, getting high, playing stupid games and pretending to set up a celebrity-sex Web site, Ben shuttles between his growing love for Alison and his terror of getting sucked into the grown-up world.

Line for line, Knocked Up isn’t quite as funny as The 40-Year-Old Virgin, which got most of its laughs from the friction between prissy Carell and his sex-crazed stoner co-workers. But it is equally good as a nutty anthropology of marginal living and as an illustration of how much energy it takes to do nothing in a work-obsessed society. Perhaps the movie’s best joke is that Alison’s milieu, which is dominated by her ball-buster of a sister (played to the WASPish hilt by Apatow’s wife, Leslie Mann, whose hostile exchange with a black nightclub doorkeeper alone violates enough Hollywood no-nos about age and race to have earned the movie its R rating) and her cowed record-producer brother-in-law (Paul Rudd), makes an exhilaratingly poor case for maturity.

A self-confessed former dweeb and now a happily married family man, Apatow effortlessly lampoons both worlds without dumping on either. He isn’t defensive enough to be a rebel, and he’s too far along with his life to be a Young Turk. At once too broad and too tender for satire, his comedy is realism plus exaggeration, plus dirty talk, plus an unexpectedly sweet moral core that tells us life’s a mess in which the best we can do is grope and muddle our way to a kind of decency. In less outré hands, the baby pictures that frame the closing credits would make me gag. In Knocked Up, they feel earned.

KNOCKED UP | Written and directed by JUDD APATOW | Produced by APATOW, SHAUNA ROBERTSON and CLAYTON TOWNSEND | Released by Universal Pictures | Citywide

Knocked Up Trailer

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