“Rocket Science” joins a long line of movies about teenage outcasts struggling to find their place in the world; two years ago the prize entry was “Thumbsucker.” But this sharp and painfully funny coming-of-age story—a hyperarticulate comedy about an inarticulate boy—manages to avoid just about every cliché of the genre. Each time you fear it’s going to go for the obvious, it upends your expectations. Writer-director Jeffrey Blitz previously made the irresistible 2002 documentary “Spellbound,” about kids in spelling bees. “Rocket Science” is his first dramatic feature, and it has a quirky literary voice all its own—self-conscious, but so sure-footed it earns its right to preen now and then.

When Hal becomes the focus of Ginny’s fierce attention, he’s not just surprised, he’s smitten. Love and sex are constantly on his mind, and everywhere he turns he sees people smooching, a reminder of his inexperience. After his dad (Denis O’Hare) packs his bags and leaves, Hal has to watch his mom (Lisbeth Bartlett) start up a new affair with the Korean-American neighbor, Judge Pete (Stephen Park)—they can’t keep their hands off each other. The judge’s nerdy son, Heston (Aaron Yoo), joins Hal’s small circle of goober pals, which includes the budding voyeur Lewis (Josh Kay), who spies on Ginny from his bedroom window. Adding to Hal’s miseries is his angry, compulsive older brother, Earl (Vincent Piazza), who rarely misses a chance to terrorize his stuttering sibling. These are all wonderfully bizarre, and very real, characters, vividly brought to life by a cast of refreshingly unfamiliar faces. Best of all is Thompson, who lets us see the sly intelligence and quick wit lurking behind Hal’s frustrated, tongue-tied appearance.

The debate topic he and Ginny must prepare for is, wouldn’t you know, abstinence. One of the pleasures of Blitz’s film is that it immerses us in the fraught, competitive pressures of the high-school debate world—like “Spellbound,” it gets the details right. Blitz’s brainy kids, who run the gamut from the pathetically awkward to the brazenly self-assured, from the nastily scheming to the hopelessly geeky, are a far cry from the usual horny adolescents Hollywood comedies serve up to flatter their target audience. They’re no less hormonal, but a lot more human.