In the town of Greendale in Northern California, high school student Lane Meyer's two main interests are skiing and his girlfriend of six months, Beth. Shortly before Christmas, Beth dumps Lane for the handsome and popular captain of the ski team, Roy Stalin. Roy is an arrogant bully who unfairly rejects Lane at ski team tryouts. Beth also criticizes Lane's car, an old station wagon. Although Lane also owns a 1967 Camaro, he has not been able to get it running and it sits in the driveway in a dilapidated state.

Lane lives in a suburban development with his mother, Jenny, a ditzy housewife who routinely concocts creepy (and creeping) family meals; his genius little brother, Badger, who never speaks but at the age of "almost 8" can build powerful lasers and attract trashy women from "How-to" books; and his lawyer father, Al, who daily tries to stop the menacing paperboy, Johnny, from breaking his garage door windows with thrown newspapers. Furthermore, Johnny claims that the Meyers owe him two dollars for newspapers, and persistently hounds Lane, yelling "I want my two dollars!" Lane also regularly encounters two Japanese drag racers, one who only speaks in Japanese and the other who learned to speak English by listening to Howard Cosell.

Lane cannot get past Beth's rejection and decides that death is the only way out of his misery. He makes several half-hearted attempts at suicide, which all comically fail. With the help of his best friend, Charles de Mar (who in lieu of not being able to get "real drugs" in their "bodaciously small town," constantly inhales everyday substances like Jell-O, snow, and nitrous oxide from a whipped cream can), Lane tries to ski the K-12, the highest peak in town, in hopes of getting Beth back, but wipes out. Lane is further embarrassed when he gets fired from his humiliating fast food job at Pig Burgers in front of Roy and Beth, who are there on a date. To top it all, he increasingly begins to suffer from neurotic hallucinations owing to the mounting frustrations in his life.

As Lane attempts to either end his life or win back his ex-girlfriend, he gradually gets to know a new girl: a French foreign-exchange student named Monique, who has a crush on him. She is staying with Lane's overbearing neighbor Mrs. Smith, who continually tries to force Monique into being a girlfriend for her socially awkward son Ricky. The pair are so annoying that she pretends she cannot speak English. Monique, a Los Angeles Dodgers fan, turns out to be an excellent auto mechanic and skier who helps Lane fix his Camaro and tries to build his confidence. When Roy insults Monique, Lane challenges him to a ski race down the K-12, with the winner to be captain of the ski team. Monique helps Lane prepare for the race, which he ultimately wins despite losing a ski and being pursued by Johnny. Beth rushes to embrace Lane at the finish line, but he rejects her and after besting Ricky (who attempts to keep Lane from rescuing Monique from the restraints of his mother) in a ski-pole swordfight, drives off with Monique in his Camaro. Lane and Monique are last seen kissing on home plate at Dodger Stadium, with Johnny bicycling towards them, while in a mid-credit scene Badger launches a homemade space shuttle from his room through the roof of the house.