Whereas past hits from the Judd Apatow movie machine (such as The 40 Year Old Virgin, Knocked Up and Superbad), have featured offbeat plots, Forgetting Sarah Marshall is his first attempt at a more typical storyline.

Meet Peter Bretter (Jason Segel): aspiring composer, loving boyfriend and all-around good guy. His day job has him composing the score for the CSI knockoff “Crime Scene,” but what he really aspires to do is write his own rock opera (the subject of which I won’t spoil for readers). Our average Joe also finds himself in a seemingly perfect long-term relationship with the lead actress of said TV show, rising star Sarah Marshall (Kristen Bell of “Heroes”).

In the spirit of a Superbad-style shocker of an opening scene, the first five minutes of the movie will either have you convulsing with laughter or getting up to leave. But stick with it — the bulk of the movie packs as many laughs as you would expect from the best comedy team around.

If you don’t already know, Sarah breaks up with Peter, who proceeds to mope around and whine about his lost love. This gets a little tiresome, with the only humorous moments coming when Peter decides that the best way to get over his ex is to have a series of one night stands, which leave him crying like a baby.
The plot picks up, however, when Peter follows the advice of his brother-in-law Brian (Bill Hader of “Saturday Night Live”) and gets away from everything that reminds him of Sarah. He pulls a “How Stella Got Her Groove Back” and jets off to Hawaii, only to run into — you guessed it — Sarah. But she’s not alone: Turns out, she’s there with a sexpot British rock star named Aldous Snow (Russell Brand).

Rather than the relaxing vacation he was hoping for, heartbroken Peter finds himself running into the couple at every turn. A particularly hilarious scene has an Aldous-obsessed bell boy, played by Superbad’s Jonah Hill, bringing the rocker on stage for an impromptu serenade during a resort-wide luau. Dejected and depressed, Peter drinks himself into a daze, making friends with a clueless newlywed, a stoner surf instructor and a cook from the breakfast buffet along the way.

Luckily for Peter, the charming receptionist at the resort is the distractingly tan Rachel, played by “That ’70s Show” alum Mila Kunis. While showing him her local haunts, the two bond over their disastrous past relationships. The chemistry is palpable, and their growing friendship leads to a romantic hike to a cliff overlooking the ocean, where they defy their fears and take a (rather ungraceful) leap into the ocean together. You know the rest.

A common theme in past Apatow comedies, the flabby everyman once again takes center stage in Sarah Marshall. But this time, he is weepy and sensitive, curiously displaying traits typically reserved for female romantic leads. As a result, Sarah Marshall is almost, scene by scene, an inverted chick flick.

Segel, a member of the old guard from Freaks and Geeks days, doesn’t fit into the Seth Rogen/Jonah Hill mold — in other words, he doesn’t look like a complete loser. Maybe it was to lend some realism to his match with Kunis, and sure, he’s supposed to be on an island vacation, but Segel seems to have spent a little too much time in a tanning booth to be a believable average Joe.

Nonetheless, the film (written by Segel himself) certainly puts a clever twist on the romantic comedy. While staying true to a predictable plot, the jokes are spot-on and cleverly handled by Segel and other Apatow regulars Hill, Hader and Paul Rudd. As usual, many of the scenes that elicit the biggest laughs are delivered by minor characters in the ensemble.

On his end, Brand is hilarious and manages to make Aldous Snow both utterly ridiculous and, eventually, somehow likeable. I wish I could say the same for Sarah Marshall’s leading ladies, but Kunis doesn’t quite shed the ditzy skin of Jackie (her character on “That ’70s Show”) to make Rachel anything more than the typical love interest. Bell, on the other hand, manages to hold her own for most of the film, although it must be said that not much is really asked of her character as far as comedy goes.

As a whole, Forgetting Sarah Marshall is not as inventive as The 40 Year Old Virgin, nor quite as funny as Apatow’s other monster hits Knocked Up and Superbad. That said, this film is still hilarious and blessed with the Apatow touch — so sit back, relax and get ready to quote from Sarah Marshall for weeks to come.