The screenplay for "Superbad" is said to have been originally written by Seth Rogen and Evan Goldberg when they were all of fourteen years old. Some touchups and additional drafts notwithstanding, this is key to why the film—an R-rated teen comedy of rib-tickling vulgarity and sobering sensitivity—seems so true to life. At least in part, Rogen and Goldberg were experiencing many of the same things as their characters, and had firsthand knowledge of the way boys of a certain age talk to each other and, in general, see the world. For that, "Superbad" hits a truthful chord that so often is glossed over with mainstream movies of its ilk.

In keeping with its semi-autobiographical genesis, the protagonists are named Seth (Jonah Hill) and Evan (Michael Cera), best friends on the verge of their high school graduation. With the knowledge that Evan is headed to Dartmouth in the fall and that Seth is, well, not, it is very clear that life is about to change and the safety net of their friendship is destined to be pulled out from under them. Having never been social enough to take advantage of their adolescent years, Seth and Evan vow to attend a big party that classmate Jules (Emma Stone) is throwing. With the nebbish, dweebish Fogell (Christopher Mintz-Plasse) about to receive a fake ID, they offer to pick up the booze on Jules' list.

What Seth and Evan do not anticipate is that Fogell's ID is going to be for a 25-year-old Hawaiian organ donor named McLovin; that their trip to the liquor store will be interrupted by a robbery and Fogell, posing as his new alternate identity, will be whisked away by two police officers, Slater (Seth Rogen) and Michaels (Bill Hader), who are into partying just as much as he is; and that Seth being hit by a car will send him and Evan off on their own series of misadventures. By the end of the night, Seth and Evan are deadset on finally making it to the party in the hopes of getting one last chance before graduation to woo crushes Jules and Becca (Martha MacIsaac).

From much of the same team responsible for adult comedy hits "The 40-Year-Old Virgin" and "Knocked Up," sans director Judd Apatow (who slides into the producer's chair), "Superbad" has a similar brand of bawdy humor mixed with enough reality-based material to keep it grounded. Like those other two pictures, it is also a tad on the overlong side; trimming down the draggy middle act could have helped the pacing and cutting out the frivolous cop characters would have kept the focus on Seth and Evan, where it deserves to be. Even if the film has a free-floating, rambling feel—1993's "Dazed and Confused" must have been an inspiration—it also is frequently hilarious, impactfully nostalgic, and gradually sentimental insomuch that two male buddies who are about to go their separate ways can be.

Most appreciatively, director Greg Mottola (1997's underrated "The Daytrippers") and screenwriters Seth Rogen and Evan Goldberg break down the wall of clichés and overdone portrayals of cliques that a lot of teen movies fall into the trap of. In the world in which these characters live—each one of the principles, both male and female, is presented as intelligent free-thinkers—high school is not a black-and-white world of popular kids and geeks, but of young people of a certain age coexisting together and trying their damnedest to make it to the other side. Some go to more parties than others and the like, but one-note jocks and cheerleaders are nowhere to be found, and there's a chance that the pretty girl might like (as a friend or even more) the overweight or slightly-built nice guy. Amen.

Time and again, "Superbad" is authentic in its observations of Seth, Evan and Fogell, as well as possible love interests Jules and Becca. Watching these people, whether they are trying pitifully to buy alcohol underage, taking peeks at the adult magazines in the convenience store, getting sloppy-drunk and sick at parties, having imperfect sexual encounters, confessing their love to one another in a naked moment of emotional bleeding, or even admitting to having a fetish with sketching elaborate drawings of penises, they are symbolic in one way or another of all of us who have ever been seventeen. "Superbad" can be very, very funny—as funny as any film that has come out this summer—as in Seth's multiple, increasingly ludicrous imaginings of how he might be able to buy liquor at a grocery store, or in one character's drunken attempt to seduce another, or in any of Fogell's (aka McLovin's) unsuspecting moments of glory. The kicker is that, underneath the raunch and outrageousness, is a heart (think 1999's "American Pie").

Jonah Hill (2006's "Accepted") is a revelation as the chubby, socially awkward Seth, and Michael Cera (TV's dearly departed "Arrested Development") is lovable as perpetually uncomfortable but innately good Evan. Both are fine young comedic actors who know how to deliver an acerbic line or a priceless facial expression, but they are just as convincing when things turn serious. Hill and Cera come off as genuine best friends, which is crucial for the arc of their relationship to work.

As Jules and Becca, Martha MacIsaac (2005's "Ice Princess") and feature-film newcomer Emma Stone are impressionable, down-to-earth, and not totally shut out of the physical comedy arena. And, finally, one would be remiss not to mention the immeasurable contributions of Christopher Mintz-Plasse as Fogell, better known as McLovin. Mintz-Plasse is a quirky slice of brilliance and steals every scene he is in. His McLovin is destined to go down in the hall of fame of great teen movie characters. As joyriding police officers Slater and Michaels, Seth Rogen (2007's "Knocked Up") and Bill Hader (2007's "Hot Rod") are the weak links. More specifically, Rogen and Hader are well-equipped for their roles, but the problem is that their roles are too broad and cartoonish to mix well with the rest of the story.

As already delved into, "Superbad" isn't without a few blemishes, and the lack of an indelible soundtrack is also missed. Nevertheless, the film is smarter and more mature than one expects from the genre, and the casting of actors who look like actual high school students rather than artificial Hollywood twentysomethings is a welcome change of pace. The ending, not going for an easy gag but leaving things open-ended, upbeat, and yet appropriately bittersweet, is perfect. In many ways, the final scene marks the end of an era for Seth and Evan as doors to their future open up ahead of them, each one leading in a different direction. "Superbad" is a successful laugher, no doubt about it, but what lingers afterwards is the poignancy of childhoods reaching an end.