"Fun Size" covers the high school party comedy checklist well, but doesn't make its own mark on the genre. Well written but weakly executed, it's difficult to imagine anyone is going to cherish the film, if they even remember it in three months.

"Fun Size" is the directing debut of Josh Schwartz, who developed the teen television dramas "The O.C." and "Gossip Girl." He didn't write the script, but the film reflects his ability to capture young people authentically, while simultaneously translating for older generations. His fingerprints are all over the narrative. Example: In the Schwartz universe, all so-called nerds are exactly one accessory (usually a pair of dorky glasses or a jacket) from looking like a model.

He also executes the John Hughes trick of making parents seem alien but still likable. In about four minutes of screen time, Ana Gasteyer as a lesbian mom reaffirms that she's among the most underrated "Saturday Night Live" cast members of all time.

Teen science whiz Wren (Victoria Justice) has captured the attention of her high school's alpha male. Fellow geek Roosevelt (Thomas Mann) completes the love triangle. On the way to the big party, Wren's prank-loving 8-year-old brother gets lost trick-or-treating. The last two-thirds of the movie is a combination of "Problem Child" and "The Fugitive," if both were reimagined as a 1980s Molly Ringwald vehicle.

The story lacks momentum, with a particularly useless subplot involving a convenience store clerk.

"Fun Size" seems trapped in a limbo between a hyperkinetic comedy for kids and something more outlaw for teens.

Screenwriter Max Werner, a veteran of "The Colbert Report," shows he can write a good script under any circumstance. Individual moments shine, such as Wren's hero worship for Ruth Bader Ginsburg, and a witty scene where Wren's mom (Chelsea Handler) bonds with the parents of her too-young boyfriend's best friend.

And then there's the destruction of Roosevelt's Volvo, borrowed from his mothers, which is violated in a particularly entertaining way. On the teen comedy scale, it falls somewhere between the fate of Joel Goodson's dad's Porsche in "Risky Business" and Charles Jefferson's car in "Fast Times at Ridgemont High." Hope someone's old man has an ultimate set of tools.