Louise is working in a fast food restaurant as a waitress and has some problems with her friend Jimmy, who, as a musician, is always on the road. Thelma is married to Darryl who likes his wife to stay quiet in the kitchen so that he can watch football on TV. One day they decide to break out of their normal life and jump in the car and hit the road. Their journey, however, turns into a flight when Louise kills a man who threatens to rape Thelma. They decide to go to Mexico, but soon they are hunted by American police.

In the season five episode Marge on the Lam, Marge takes her neighbor Ruth Powers to the ballet because Homer is litterally stuck between two candy machines at work. They had a good time and decide to go out again, in what turns out to be one big Thelma & Louise parody. Click on the screenshots from the movie for full size images.

Season 5 - 1F03 - Marge on the Lam

Ruth picks up Marge in the car she has stolen from her husband, and says that this night is all about: "sunshine, lollipops and rainbows" - according to the music she puts on. She quicly realises that it was the wrong tape and switches to some rock music.

  Louise picks up Thelma. Thelma hasn't told her husband about the fact that she's going on a vacation because she knows that he wouldn't allowed it.

Plus the fact that the car Ruth is driving is quite similar to Louise's, there's a big reference when we see that both Thelma and Marge decides to go out and have fun despite their husband's wiches. "How can you do this Marge? How can you desert your children?!?" -Homer


A Guy comes up to Marge and Ruth and asks if she feels like getting lucky. Marge replies that she is lucky. The guy says that he always gets what he wants.

Marge: I said NO!
Guy: Oh, did you? Oh, I completely misunderstood. Please accept our apologies.

  A guy named Darryl starts talking to Thelma. Many drinks later he tries to rape Thelma on the parking spot and won't take: "No!" for an answer. Louise then points the gun to his head and forces him to stop. When Darryl is being rude to them and says that he shouldn't have stopped Louise shots him.
Sticking together
Ruth stops at a truck stop and lets Marge call home, so she won't be involded in the crime.   Thelma is calling home to check if the police is after them. When her husband is being unusually polite to her she hangs up immediately.
Both Thelma and Louise refers to how important it is that they stick together. At the truck stop (which by the way is named "The Seething Sisters.") Marge sees several couples talking with the same southern states accent Thelma and Louise got, about the importance of sticking together.
The waitress at the truck stop complaines about how the waffles stick together, to which the cook replies: "Stickin' together is what good waffles do!"   In the beginning of the movie we can see that Louise is working in a cafeteria, which most likely also is meant as a part of the parody in the simpsons' episode.
"This cross-country flight from the law would be hell if we didn't stick together."    
Shoot out
The women stops in a field where Ruth shows Marge her gun:
Marge: "You're not going to hunt me for sport are you?"
Ruth laughing: "Relax Marge I'd never turn a gun on a human being. My husband on the other hand."
  Early in the movie Thelma asks Louise to take care of her husband's gun.
Ruth aimes the gun towards a couple of old cans before she lets Marge try, then an old man shows up and mourns about his "precious antique cans."   Thelma and Louise tricks a truck-driver who has sexually harassing them several times into following them. When they stop, they demand an apologize. The truck-driver refuses to apologize so they start shooting at his truck, until it explodes.
The Car Chase
Chief Wiggum and Homer catches up with Ruth and Marge again when they drive by them, soon they're followed by the entire police squad.    

Channel 6 reports about the chase:

Brockman: At the risk of editorializing, these women are guilty, and must be dealt with in a harsh and brutal fashion. Otherwise, their behavior could incite other women leading to anarchy of biblical proportions. It's in "Revelations", people!

Homer uses the megaphone to apologize for their entire marriage up to this point and begs the women not to drive into the chasm. Marge and Ruth were unaware of the chasm and stops right infront of it, while Homer and Wiggum drives straight into it.   The women manage to get rid of their pursuers, but when the police helicopter comes after them they don't stand a chance. They notice the cliff and stops, but when they realize that there's nowhere to escape they decide to drive into it.
Just as seen in the movie we can see Homer and Chief Wiggum drive into the chasm and same way the producers freezes the image and let it fade into white.
When the picture comes back we see that the men drove straight into a pile of dust.    
HAH! And to think those idiot environmentalists were protesting this landfill.    
Plot from imdb.com. All screenshots and text except the plot by Henrik.