The Simpsons franchise doesn't break any new ground in its long-awaited big-screen debut. But unless you're one of those people -- most likely born before World War II -- who dismiss the show because it's a cartoon or because its brand of humor is too cheeky and irreverent, odds are you'll be rolling in the aisles.

Even though the movie isn't particularly daring or adventurous, diehard fans will be happy to finally be watching Homer and company projected large after eighteen years on the small screen. And since the movie amounts to an extended episode, it actually stands a better chance of winning over doubters to the show.

Nearly four years in the making, The Simpsons Movie has a slightly sharper edge than the series. There's more physical violence, along with a few obscene gestures and exclamations that wouldn't pass muster with the FCC. The butts of the satirical jokes are familiar:  religion, the environment, Disney, homosexuality, and the Kennedy clan (toothy and bug-eyed) come in for ribbing that's in the same ballpark as the series. Likewise, the animation is brighter and crisper yet true to the hand-drawn spirit of the show.

"D'Oh" means doomsday for Springfield thanks to Homer (voiced as always by Dan Castellaneta), who will surely go down as one of the more blundering and boorish fictional American males ever -- the ultimate selfish loser with an inexplicable capacity for engendering affection. Homer nearly goes too far this time, inviting the ire of the entire population of Springfield, the Environmental Protection Agency, and his forgiving wife Marge (Julie Kavner). He screws up so bad that Bart is driven to envy the fatherly attentions of nerdy neighbor Ned Flanders. Father and son have always been at each others throats, but this is serious.

Homer's transgression? He adopts a pet pig and -- in a hurry to scarf free donuts -- decides to dump the porker's waste in the town lake, which causes Springfield to be named the most polluted city on the planet. The federal government (led by President Schwarzenegger) then seals the city in a gigantic dome. The townspeople turn ugly and the Simpsons must beat a hasty retreat, ending up in Alaska of all places.

This chain of events also entails some milestones for other members of the family. Grandpa has a prophetic seizure in Church, Lisa gets an Irish boyfriend, and Marge reaches the limit of her forgiveness and understanding. Family values are still affirmed in the end, and the message means more for the trials the family endures. The focus is squarely on them here. Guest stars have been a fantastic part of the show since the early days, with everyone from Elizabeth Taylor to British Prime Minister Tony Blair lending their voices. But with one major exception (Tom Hanks) the stage is cleared for the blood relations. Not even any of the regular denizens of Springfield play a major part. Maybe the creative team simply couldn't choose between supporting players to feature in a prominent role.

Whatever the reason, the writing is so shrewd that it's not necessary to try and incorporate everything from the show or resort to stunt casting or gimmickry. Even the sight gags are clever: "Binge Responsibly" reads a beer ad. Or Homer's mournful question: "Why does everything I whip leave me?" One of the movie's best sequences has Bart skateboarding naked, and it's punctuated by a shot of his privates and Chief Wiggum exclaiming, "Stop in the name of American squeamishness!"

As the best satire must, the self-aware movie takes a few pokes at itself. Early on, Homer jokes that it's ridiculous to pay good money to watch in the theater what you can see at home for free. He's wrong of course. It's well worth the price of admission if it makes us laugh. Just as Homer has an epiphany before deciding to do the right thing, those few who doubt the importance of the series will experience the sudden realization of a great truth: The Simpsons is one of the best and most influential TV shows ever.

(Released by 20th Century Fox and rated "PG-13" for irreverent humor throughout.)