Ferris Bueller (Matthew Broderick), a student in the comfortable suburbs of Chicago, is an irresistible smoothie -- he glides through life, a Jay Gatsby to his classmates, getting everything he wants. He's a virtuoso of sweet manipulation and master of the "sick out," so when the morning radio reports a beautiful spring day, he decides to fake an illness and skip school.

His comrades in this venture are his chum Cameron (Alan Ruck), a nervous, awkward kid whose father bullies him, and girlfriend Sloane (Mia Sara), a cutie who'd follow Ferris anywhere and, through the course of the movie, does. His adversaries are his unsuspecting parents and the school disciplinarian, Ed Rooney (Jeffrey Jones), who suspects everything.

And his tols are the technological toyus of a privileged teen, including a computer (which he uses to alter his school records), a synthesizer (with which he manufactures the various coughing and gurgling sounds of his "illness"), telephone answering machines and the telephone itself. As Hughes deftly works these props, to the vivid consternation of the snake-like Rooney, the first half hour of "Ferris Bueller's Day Off" is an easy ride, fueled by a riotously funny cameo by screen writer Ben Stein as the most boring history professor God ever created.

Composer Ira Newborn's playful music, an eclectic mix of new wave, neo-'60s rock and homages to film and TV scores, moves things along, too, but after that first half hour the movie starts to flag, and soon after that it dissolves into what is pretty close to a complete mess. "Ferris Bueller's Day Off" founders on the same reef as all of Hughes' movies, from "Sixteen Candles" to "The Breakfast Club" -- either he has no sense of story construction or, worse, he just doesn't care.

The emotional core of the movie belongs to the subsidiary character, Cameron, who has to learn to stand up to his dad; it's not just that Hughes' teen moralism here is typically banal, but that it has little to do with the motion of the story generally, and less to do with Ferris, who commands the story's center. The character of Ferris, on the other hand, is nothing more than his continuing hijinks -- Hughes never gets inside him in the way that Paul Brickman got inside the fundamentally similar hero of "Risky Business." The whole script is off-balance.

So "Ferris Bueller's Day Off" proceeds as a downhill series of riffs. There is an extended (and exceedingly familiar) farce routine, borrowing broadly from the "Pink Panther" series, in which the hapless Rooney steps in mud, gets bitten by a guard dog, is assaulted by a karate-trained young girl and has his car towed away. The technological tricks with the stereo and the phone machines continue throughout, with consistently diminishing comic returns. There is a subplot, more or less stolen from "Risky Business," involving the destruction of a Ferrari. And so forth.

Broderick, a likably fresh-faced young actor with enormous technical gifts, plays the material well, but there's owfully little material for him to play -- the throwaway ironies of the role make him seem affected and kittenish. Ruck is set loose to improvise, which results in mugging nearly as embarrassing as Jon Cryer's in the last Hughes epic, "Pretty in Pink," and when he launches into his big emotional speech at the end (the "My old man pushes me around . . ." speech), only an inveterate rubbernecker would want to watch him.

At the expense of sounding like Norman Podhoretz (and that's a high price to pay), the unavoidable conclusion is that all those crabby cultural conservatives who bemoaned the '60s were right -- the tyranny of youth has proven a nearly unmitigated disaster for American movies. At one point in "Ferris Bueller," Sloan and Cameron are discussing college and the future. "What are you interested in?" she asks. "Nothing," he replies. "Me either," she says. The moment is presented wholly without irony, and you have to wonder why anyone would want to make a movie about such mindlessly dull rich kids, or why you'd want to spend 100 minutes in the dark with them. Ferris Bueller's Day Off, at area theaters, is rated PG-13 and contains profanity.