At first, Peter does all the stereotypical things guys do to nurse a broken heart: he picks up women for meaningless sex, he tries to drown his sorrows in alcohol, and he lazes around his apartment in sweatpants, watching TV. None of it makes him feel any better. His step-brother Brian (Bill Hader) suggests he take a vacation to get away and forget all about Sarah. Peter decides to check out a Hawaiian resort that Sarah had often talked about. When he gets there, he discovers that his ex has also checked in with the guy she dumped Peter for, a narcissistic rock star named Aldous Snow (Russell Brand).

That's the set-up; the rest of Forgetting Sarah Marshall follows what happens as Peter struggles to get back on his feet as he keeps running into the woman who dumped him. The point is that it's hard to "forget" someone you cared about. Even after you break up, you tend to carry them around for a while, like a heavy piece of luggage. Peter grows jealous thinking about Sarah with another man. The jealousy turns to depression, which eventually gives way to anger. He discusses the situation with other people he encounters on the island, including a stoner surfing instructor (Paul Rudd), a sexually frustrated newlywed ("30 Rock" star Jack McBrayer), and, most significantly, the resort's front desk clerk, Rachel (Mila Kunis). Rachel has been through the breakup wringer too, and she empathizes with Peter's plight, often trying to help him rediscover his strength. But everytime he starts to feel strong again, there's Sarah, and even the most awkward interaction with her threatens to send him crashing again.

The reigning name in movie comedy these days is Judd Apatow who, as writer, director, and producer (or sometimes all three) has cornered the market with films that combine raunchy R-rated humor and genuine heart. This time, Apatow is producing the screenplay written by Segal, a frequent collaborator. (Another collaborator, Nicholas Stoller, directs.) Forgetting Sarah Marshall therefore contains all the elements that made The 40 Year-Old Virgin, Knocked Up, and Superbad such big hits.

The most blatant of those elements is, naturally, the edgy humor, which is often - but not always - sexual in nature. There are at least a dozen really huge laughs in the film, and a couple dozen more big ones. The nude breakup is certain funny (in a weird kind of way), as is a sex scene toward the end, which has to rank as one of the most hilarious copulation scenes ever. (It involves two couples in adjoining rooms.) The movie also finds humor in Peter's burgeoning awareness that life with Sarah wasn't all roses. In spite of the fact that he pines for her, each island encounter with Sarah reminds him of something that wasn't quite right in their relationship. During a very witty flashback scene, we see him acting as a lackey to his glamorous girlfriend instead of being an equal. I laughed at lot at the picture, and what's best is that the humor springs from relatable situations and the genuine emotions of the characters.

And that is the less-blatant, but most impressive, element of the Apatow formula. Forgetting Sarah Marshall may have an abundance of adult humor, but that's only because it's dealing with adult issues. Segal's screenplay is uncommonly wise about break-ups. As both a writer and a performer, he knows that break-ups are frightening and sad, yet also occasions for self-growth. Over the course of the movie, we see Peter Bretter go from complete devastation and misery to a kind of inner peace. He initially thinks the split with Sarah will kill him, but slowly realizes that quite the opposite is true. The movie suggests that only in hindsight do we see our failed relationships for what they really were, and from there we can evolve.

My first exposure to Jason Segal was in two Apatow-produced TV shows, "Undeclared" and "Freaks and Geeks." In the former, he played an obsessively jealous boyfriend. In the other, he was an outcast stoner desperately in love with a girl who only valued him as a friend. Those roles - as well as the one of Peter Bretter - suit Segal like a glove. He's able to be outrageously funny and enormously sympathetic at the same time. Segal isn't afraid to show us the character's vulnerabilities, either physically (the nude scene) or emotionally (Peter occasionally cries like a baby). This is a really fantastic comedic performance.

I also liked Mila Kunis, whose function in the story I haven't said much about. Her character Rachel serves as a beacon of hope for Peter. She's the one telling him that he'll be okay and, more importantly, making him believe it. Kunis has been in a few forgettable movies following her work on "That 70's Show," and I think her excellent work in this movie could propel her to bigger things on screen. She lights up the screen as this good-hearted young woman. Same goes for Russell Brand, who is charmingly obnoxious as the egotistical rock star.

Most - if not all - of us have been through a really bad break-up at some point. Forgetting Sarah Marshall gets so many of the details right: the humiliation, the self-pity, the need to latch onto something (anything) like a life preserver to get through. In that sense, the movie is very wise. It's also unbelievably funny, proving again that the line between comedy and tragedy is a thin one. Forgetting Sarah Marshall makes you laugh and squirm in recognition at the same time. It's quite an amazing feat.

( 1/2 out of four)

Forgetting Sarah Marshall is rated R for sexual content, language and some graphic nudity. The running time is 1 hour and 51 minutes.

To learn more about this film, check out AskMen.com: Forgetting Sarah Marshall