"21 Jump Street" thrilled me to itsy-bitsy elated pieces. The Reagan-era TV series that inspired this inspired comedy was serious about its laughable premise. A team of young-looking police officers went undercover as high school students to investigate youth-related crimes.

In the revival, Jonah Hill and Channing Tatum play high school antagonists turned police academy grads who find themselves thrown together in an identical back-to-school operation. Their captain (Nick Offerman of NBC's "Parks and Recreation") explains the program was revived because "the people who think these things up have no creativity or imagination. All they do now is recycle (stuff) from the past and expect us not to notice."

Recognizing the shamelessness of its own premise and holding it up to ridicule is one of the reasons this is a model spoof. There are plenty of old jokes and stock situations in the script, but the movie hits them from new angles with a gusto that's downright startling. Even when the material isn't fresh it's spun in ways that catch us off-guard. Thrills, farce, flashes of genuine emotion — this movie really knows how to party.

The dual protagonists are ideally mismatched and played to a T. With his high-pitched jabber, Hill carries the verbal humor. Tatum, the jock lunkhead, throws himself into the story's physical comedy with the frenetic zeal of a rodeo clown. Re-enrolled in high school to bust a drug ring, they find themselves reliving the insecurities and jealousies that plagued them a decade before. Hill chokes up and stammers around girls; Tatum has his pretty chemistry teacher hyperventilating, but he's embarrassed that he's not really, you know, smart.


But the busy, well orchestrated script (co-written by Hill) doesn't stop there. The tough-guy posturing that made Tatum high school royalty back in the day is passe. Today's students are hardworking and enlightened and politically correct. Now Hill hangs with the hip crowd while Tatum languishes with the nerds. "It's because of 'Glee.' Damn you, 'Glee,' " he grouses. Tatum's heart splinters when he overhears Hill call him "Rain Man" without the math skills. The way he makes big sad teddy bear eyes at Hill afterward is plaintive and goofy all at once.

Directed by Phil Lord and Chris Miller ("Cloudy with a Chance of Meatballs") "21 Jump Street" deconstructs itself as it sprints along, mining irony from the conventions of romcoms, buddy-cop flicks and fish-out-of-water comedies. There's a triple-layer gag about egregious car-chase explosions. Ice Cube delivers bug-eyed intensity as a short-tempered police captain who's well aware that he's a stereotype incarnate. Hill lands the title role in the school's disastrous production of "Peter Pan," a nod to the forever-young premise of the film itself. Then comes a prom-night climax almost as blood-spattered as the one in "Carrie," and a whole lot funnier.

"21 Jump Street" goes to obvious places for cheap laughs, and stoops for several giggly gross-outs, but more often, it zonks us with loopy, eccentric ingenuity.