It’s the summer of 1987, and James Brennan (Jesse Eisenberg, below left), an uptight comparative literature grad from Oberlin, can’t wait to embark on his dream tour of Europe with his best friend. But when his parents renege on the trip’s subsidization, James has little choice but to get a job, and spend his last summer before grad school at a seasonal amusement park operated by a loopy young married couple (Saturday Night Live‘s Bill Hader and Kristen Wiig).

Forget about German beer and reefer-infused philosophical discussions, museums and pliable French girls — James’ summer will now be defined by screaming kids high on cotton candy, soused patrons scheming to score giant stuffed pandas and an old elementary school acquaintance always trying to punch him in the balls. Lucky for James, he makes a quick friend in Joel Schiffman (Martin Starr), a droll, pipe-smoking game booth worker who helps initiate James into the absurd conventions and rituals of theme park life. He finds an older mentor in the park’s maintenance guy, Mike Connell (Ryan Reynolds), a local heartthrob due to the rumor that he once jammed with Lou Reed. And yes, James even inches closer to losing his virginity, discovering love — or at least concentrated lust — in the form of two co-workers, the captivating if slightly withdrawn Em Lewin (Kristen Stewart, below right) and dance-happy, carefree Lisa P. (Margarita Levieva).

Fresh off helping deliver a hit with Superbad, writer-director Greg Mottola returns to the big screen with his first original script since his 1997 debut, The Daytrippers. Adventureland is rooted in biographical torture (Mottola worked at a Long Island amusement park while attending Columbia University), a fact that comes through in the winning construction of the movie’s slightly off-kilter tone. Even if he’s unable to wrangle the otherwise lovely and charming Stewart’s eyes-askance lip-nibbling, or bring Eisenberg’s mannered tics fully under control, Mottola has a keen sense of detail, a deft touch with dialogue and smart taste in the casting of myriad supporting players.

One of the more intriguing elements of the film — something hinted at and flirted with in the script, but never fully and explicitly embraced, especially by the actors — is the sense that it’s an exploration of Ms. Right Now vs. Ms. Right Right Now, if that makes sense. As appealing and largely engaging as it is on the surface, Adventureland could have struck an even deeper and more thrillingly subversive chord by tapping into the idea of one (smart) kid’s randy summer in heat — the notion of a young, sensitive guy’s quest to unburden himself of his virginity while still sealing the deal with someone who he can hold a conversation with.

The product of a warped home life with a recently deceased mother and an even more recently remarried dad, Em is a hot, vulnerable mess, which comes through in her serial acting out with Connell. Other than the fact that they both seem to be generally restless, pointed toward New York City and of above-average intelligence, though, there’s little that realistically binds James and Em. Even Mottola seems bored with their interactions, sticking them together and pulling them apart in a somewhat arbitrary fashion that gives the movie a fitful rhythm. These two don’t seem like a match made forever, basically. Unfortunately, Adventureland never wholly digs into that potentially provocative mutual-use premise, and Eisenberg’s Woody Allen-lite shtick isn’t hormonally charged enough to match James’ predicament.

In the end, though, this is all criticism relative to what Adventureland gets right. With its easygoing, lived-in charms and nice supporting performances, certainly there’s a lot more good than not in the movie. It’d be an entirely suitable flick to lose your teen/twentysomething coming-of-age cherry to, in other words. (Miramax, R, 107 minutes)