The Simpsons flee Springfield in the dark of night.

TM and © 2007 Twentieth Century Fox Film Corporation. All Rights Reserved.

Fans of The Simpsons have had to wait 18 years for the first full-length feature film about the family, opening on July 27. Although the hype leading up to the release date has included unique publicity stunts -- such as a contest between 14 Springfields across the U.S. to determine who gets to host the hometown premiere, and the conversion of selected 7-Elevens to Kwik-E-Marts, complete with KrustyO's, Buzz Cola, and Squishees -- the film's producers have kept mum about the details of the plot.

However, the word on the street is that Homer, his new pet pig, and a leaking silo full of pig droppings somehow spur a large-scale environmental crisis that must be contained by the U.S. EPA. The EPA chief is a villainous Russ Cargill, who reports to U.S. President Arnold Schwarzenegger (voiced, respectively, by Simpsons veterans Albert Brooks and Harry Shearer). Somewhere along the way, Erin Brockovich makes a cameo as herself.

The Guardian got a peek at 10 minutes of the film, and notes that a cameo of Green Day in the film has the band members "poisoned and drowning in the fetid Lake Springfield after interrupting a Duff Beer-sponsored show 'to say one thing about the environment.'" Methinks that the water pollution may link back to the pig-poop issue, but that's just wild speculation an educated guess on my part. Another spoiler is that Lisa is rumored to develop a crush on a green activist while pulling together a school presentation on climate change, appropriately entitled "An Irritating Truth."

But we'll all have to wait for another week and a half to find out exactly how it all plays out, unless Fox wants to give Grist staffers a prescreening (hint, hint).