Long-time viewers know that, like most TV series, “The Simpsons” can vary wildly in quality from season to season and even week to week. There have been classic episodes—“A Streetcar Named Marge,” “Homer and Apu,” “Behind the Laughter,” “Cape Feare,” to name but a few—but some clunkers, too. Overall, though, the dysfunctional yellow clan from that mysterious-situated Springfield has maintained a remarkably high standard over nearly twenty years and more than four hundred half-hours. They’ve certainly earned their shot at the big screen.

So where does “The Simpsons Movie” stand on the Simpson quality spectrum? Well, it’s not the equal of the very best episodes—the mere fact that it has to be sustained at three times the usual length makes that almost an impossibility. But it’s not a disappointment, either. It’s akin to a solid, enjoyable entry among the four hundred shows that differs from them in lasting 86 minutes—and, of course, in being something you have to pay to see.

That last point is the key to an especially good opening bit involving a Simpsons’ day out and an Itchy and Scratchy movie. But the script, credited to no fewer than eleven writers, soon segues into a typical tale of how Homer’s bumbling ineptitude—in this case, his adoption of a pet pig—leads to an ecological disaster, the family’s expulsion from a quarantined Springfield, and their return to save their hometown from the machinations of government bureaucrats. Though told on a larger scale than the usual weekly stories about Homer’s brainlessness, this isn’t unfamiliar territory.

It is, however, supplied with a steady stream of off-handed jokes, nutty asides, sight gags and pop-culture jibes that keep things percolating nicely. There are a couple jabs at old-style Disney animation (good even if “Shrek” got there first); a few nice knocks at Fox; some ribbing of religion; and the inevitable swipes at current political targets, from Homeland Security to Al Gore’s Oscar-winning documentary (though in this respect the movie is actually less edgy than the TV show often is). And all the Simpsons have their chance to shine. Marge agonizes as usual over her hubby’s thoughtless ways, Lisa gets a potential boyfriend who’s as environmentally conscious as herself, and little Maggie saves the day on a couple of occasions. Then there’s Bart, of course, who not only does a rousing nude skateboard ride through downtown Springfield but gets to question Homer’s parenting skills in a subplot involving Ned Flanders and even stretches his acting chops with a scene in which he gets tipsy.

Virtually all the secondary characters fans have come to love show up at one point or another, too, some—Grampa, Chief Wiggum, Nelson, Cletus, Krusty, Moe, Milhouse, Comic Book Guy, Reverend Lovejoy, as well as Flanders—at considerable length while others are a bit shortchanged. (I could have used more of Mr. Burns and Apu, but that’s just a personal preference.) Unfortunately, the new kids on the block are a mixed bag. Lisa’s boyfriend Colin is bland, the Alaskan Medicine Woman who helps Homer through a crisis probably seemed funnier on the page than she is on the screen, and the big government villain—EPA Director Russ Cargill, voiced by Albert Brooks—never really takes off. One can also deplore the presence of Arnold Schwarzenegger as the President, bumping Rainer Wolfcastle from a role that was obviously made for him just because he’s a bigger name. (It’s like the awful choices sometimes made when Broadway musicals have been adapted to the screen—why Audrey Hepburn instead of Julie Andrews, or Rosalind Russell rather than Ethel Merman? Rainer, we miss you!) On the other hand, the guest shots by Green Day and Tom Hanks work out just fine.

One could quibble with a couple more choices in “The Simpsons Movie.” One or two songs would have been welcome, especially since the series has always used musical parodies so well. (Yes, there’s “Spider Pig,” but that’s about it. And its songs certainly helped “South Park: Bigger, Longer and Uncut,” the only other example of an animated show successfully making it to the screen while still on the air.) But with a widescreen look that manages to be true to the series while expanding its scope, the picture is certainly smart enough to please fans hungry—as Homer always is—for a super-sized helping of their favorite TV family.

Incidentally, this is one of the instances when you shouldn’t rush out as soon as the closing credits begin to roll. The incredibly long final crawls feature a sprinkling of excellent added gags, including one involving Maggie that a lot of viewers will hope proves prophetic.