The latest bawdy thoroughbred saddled in Judd Apatow's stable doesn't insist on its hilarity or wear pop culture references as blinders. Disregarding the smug advertising campaign, Forgetting Sarah Marshall doesn't feel like it has anything to prove, perhaps because many fences were already jumped by barn mates The 40-Year-Old Virgin, Knocked Up, and Superbad.

The ease goes both ways. We're now comfortable with this new breed dubbed Romantic Disaster Comedy, though "disaster" is surely redundant. The laughs and humorous commentary on corporate-driven escapism -- whether TV crime shows, horror movies, or celebrity frenzy -- are organic. They spring naturally from the story, along with full frontal male nudity and the most explicit sex talk heard in multiplexes since Superbad last summer.

The risqué quality is essential to the message as well, with expletives referring to ribald situations that celebrate the therapeutic value of sex while acknowledging the emotional hollowness and dangers of promiscuity. And it's all done in good fun: no character or type is roasted mercilessly. When it pushes something, as it does early on when protagonist Peter Bretter, played by Jason Segel, who also wrote the screenplay, is seen in all his glory for an extended period of time, it does so with a twinkle in its eye, so to speak.

The price we pay for this laid-back vibe is that Forgetting Sarah Marshall too often leans on convention and is therefore overlong. It's structured like a traditional romantic comedy. Boy loses girl, cries, can't get her out of his mind, and, without really meaning to, tries to win her back. Miss Marshall (Kristen Bell) is the lead in a television crime-scene drama. Peter -- the half-doofus, half-slouch she dumps after dating for five years -- composes music for the show and insists on being naked when he gets the heave-ho. Still inconsolable after a string of meaningless one-night stands, Peter flies off to a Hawaiian resort on the advice of his stepbrother (Bill Heder). Wouldn't you know Sarah and her new squeeze happen to be staying there? The cute desk clerk (Mila Kunis) takes pity on our unassuming lug, letting him occupy an adjacent suite and reminding Sarah and the audience not to count him out.

Peter's eventual conquering of one of these women is an especially endearing feature of the movie, even though it also conforms to convention. He earns the girl he's meant to be with; he deserves to be loved, not because he takes a beating for his amour or doesn't fit the stereotype of a classic romantic male lead, but because he's talented. Yes, Peter is gainfully employed at the start and has the automatic cool that comes with being a musician. Yet after undermining himself and reaching pitiable depths, he rises up with an act of creativity that goes beyond normal maturation or leaving behind the slacker lifestyle. Without spoiling any potential surprise, Peter channels his talents in a way that's satisfyingly fresh but still validates classic rom-com story arcs.

Producer Apatow and director Nick Stoller drew freely from the small screen talent pool. Segel, who also appeared in Knocked Up is a regular on the sitcom How I Met Your Mother and blond Bell is a Veronica Mars vet. Jack McBrayer of 30 Rock is cast as a virgin honeymooner with faith-based sex phobias. (His exchanges are the only time when the picture turns potentially offensive, as in blasphemous.) And those years in the sitcom trenches may have finally paid off for Kunis, who's more fetching and less screechy than she was on That '70s Show.

Apatow regulars Paul Rudd and Jonah Hill also have supporting roles, but Russell Brand deserves to be singed out for turning a stock figure, Sarah's British rock star boyfriend Aldous, into an equally risible and likeable character, "a dark, gothic Neil Diamond" according to one description. Forgetting Sarah Marshall could do with a trim and my ardor started to flag somewhat the day after I saw it, but not enough to spoil the hackneyed dream of laughing and falling in love on a tropical island.

(Released by Universal Pictures and rated "R" for sexual content, language and some graphic nudity.)