Once the largely inept and uncouth cast shuts the heck up (i.e. stops trying to act) and starts burnin' rubber and wreckin' cars, there's some good ol' fun to be had in the slipshod big-screen rehash of "The Dukes of Hazzard."

But the first hour of the movie is a punishing parade of protracted establishing, colorless characters and painful performances that make the picture's amusingly harebrained TV inspiration look like sophisticated action-comedy by comparison.

Seann William Scott (Stiffler from "American Pie") and Johnny Knoxville (MTV's "Jackass") play moonshine-running country cousins Bo and Luke Duke -- although they have little in common with the sexy charmers in cowboy hats and sparkling smiles created so charismatically by John Schneider and Tom Wopat in 1979. Scott and Knoxville have re-imagined the characters as the Appalachian equivalent of frat boys, and their acting consists mostly of screaming "woo-hoo!" as they drive around dirt roads at 80 mph.

But at least these two are good for the occasional lowbrow laugh. Candy-pop "singer" and professional celebrity Jessica Simpson steps into Catherine Bach's butt-hugging cut-off Levi's as sexpot kin Daisy Duke, and she's such a catastrophe as an actress that every time she opens her Barbie-doll mouth, just her fake Georgia drawl is enough to make your ears bleed -- never mind her fumbling dialogue. Knowing where her assets lie, director Jay Chandrasekhar ("Club Dread," "Super Troopers") does his best to keep Simpson as silent and scantily clad as possible. But even in a bikini, she seems rigid and plastic.

The rest of the characters who had been so colorful, if often obnoxious, on the TV show (idiot sheriff Roscoe P. Coltrane, hillbilly mechanic Cooter, etc.) have been reduced to forgettable stock characters. In fact, the movie's only entertaining performance comes from Willie Nelson, playing the clan's joke-telling (and now pot-smoking) surrogate patriarch Uncle Jesse.

In the porous, sloppy, slapped-together plot (as inane as the show ever was, and lathered up with PG-13 vulgarity), the Dukes must save Hazzard County from being strip-mined by the cartoonishly crooked strongman Boss Hogg (Burt Reynolds, phoning in much heinously clumsy exposition) while also winning an off-road rally in their bright orange, Confederate-flag emblazoned, thunder-engined, nearly indestructible 1969 Dodge Charger called the General Lee.

But these energetic, completely over-the-top race and chase scenes in "The Dukes of Hazzard" are such a gas that they save the movie from being a complete disaster. Just like on the TV show the General Lee spins out, screeches around corners, kicks up dust, outruns the sheriff and gets airborne whenever possible. Chandrasekhar giddily embraces the absurdity of it all, having the car drive at an angle through much of the movie, as if its back end were permanently fishtailed, and making sure every jump gets the car at least 50 feet off the ground -- even if he has to use CGI effects to do it.

The General Lee's best scene, however, is a traffic jam in Atlanta (how it got there isn't worth explaining), during which yahoo-ing rednecks, embittered minorities and uppity soccer moms in passing vehicles holler out their varied and vocal opinions of the stars-and-bars on the car's roof. It's an amusing, self-deprecating way to address "Hazzard's" unabashed celebration of good-ol'-boy culture and all that it symbolizes.

But a touch of ironic self-awareness, a little raucously entertaining stunt driving, and some spectacular crash outtakes with the closing credits aren't nearly enough to justify an $8 to $10 ticket plus popcorn. Not when "The Dukes of Hazzard" reruns -- just as dumb, just as wild, but with far more appealing characters -- are on cable TV twice a day.