Airdate - September 25, 2005
When Maggie comes down with chicken pox, Flanders gives Homer the idea to hold a "pox party" for all their friends' children who have never had the disease. Kirk Van Houten drops Milhouse off at the party and says Luann will collect him later, but Marge invites him into the kitchen for drinks, so he is still there when Luann arrives and is also invited to have a few "Marge-aritas". Luann confesses to Kirk that she's in a dating dry spell, and after many drinks, they end up making out on Homer and Marge's bed, where Milhouse finds them.
Kirk and Luann tell Milhouse that they have decided to enter into a "trial un-separation", and he is initially delighted at the prospect... until he discovers that the lack of competition for his affection means they don't do as much fun stuff together. Since Bart also benefitted from Milhouse's situation, the two conspire to break Kirk and Luann up again (reasoning that it will happen eventually anyway). Their first few attempts fail, but an episode of The O.C. gives Bart the idea to plant a bra in the Van Houtens' bed, thereby making Luann think Kirk is cheating on her and dump him again. However, he uses one of Marge's bras, and instead of dumping Kirk, Luann confronts a stunned Homer with the evidence and tells him to tell Marge to stay away from her husband. When Homer accuses Marge of sleeping with Kirk and doesn't believe her denial, she throws him out.
Desperate to repair the damage, Bart confesses the truth to his mother, but she says it doesn't change the fact that Homer doesn't trust her. Despite Lisa's attempts to persuade him that another Zany Scheme will end badly, Bart decides to create a dummy of himself to throw off a cliff and into a river in front of Homer and Marge to make them think he doesn't want to live in a world where they're divorced, but when the time comes, Milhouse accidentally pushes the real Bart off the cliff. Homer dives in to save him, but they are swept along by the current toward a waterfall. Marge yells at them to let go; proving that he does trust her, Homer obeys, and Marge is able to save her husband and son by letting them grab onto her hair after she ties her leg to a tree.
- Bungled Suicide: In Milhouse's Imagine Spot after Kirk and Luann tell him they're trying their relationship again, we see snapshots of their lives apart. One of Kirk's scenes shows him trying to hang himself, only for the noose to break.
- Cool and Unusual Punishment: When Bart confesses that he planted Marge's bra in the the Van Houtens' bed, Marge tells him she's going to erase the saved games on his PlayStation, an idea she got from Hip Punishments. She says the real problem is that Homer doesn't trust her, and when Bart asks if this means they're getting a "D-A-V-U-R-S", Marge tells him to work on his spelling or she'll erase the custom ringtones on his phone. Bart flees with a Big "NO!".
- Driven to Suicide: Bart decides to get Homer and Marge back together by pretending that he doesn't want to live if they divorce and throwing a dummy off a cliff into the river, but thanks to Milhouse not wearing a strong enough glasses prescription, Bart is the one who ends up falling into the river instead of the dummy. In the final scene, a horrified Milhouse jumps off the cliff himself, saying he doesn't want to live in a world without Bart.
- Finding a Bra in Your Car: The plot to break up the Van Houtens uses one of Marge's bras which has a name tag on it, which makes Homer think Marge is the one cheating.
- Gone Horribly Wrong: Bart's attempt to split up Milhouse's parents not only fails, but it causes his own parents to split up and almost go through an ugly divorce.
- Imagine Spot: When Kirk and Luann tell Milhouse that they are giving their relationship another shot, he has a daydream sequence to Crosby, Stills, Nash (And Young)'s "Our House". It begins with a picture of the Van Houtens tearing in half as baby Milhouse ages several years and tumbles past shots of Luann with Pyro and Disco Stu as Kirk spirals toward rock bottom, until finally both of his parents catch him. He then sees Lisa in a bridal gown, and suddenly changes into a tailcoat before joining Lisa on a bouncy ride. As he emerges from his daydream, he is revealed to be in the back of an ambulance, having apparently fainted.
- Inevitable Waterfall: When Bart falls into the river in the episode's climax and Homer jumps in after him, they are swept toward a waterfall, and Marge has to save them both.
- It's for a Book: Homer has painted a face on his belly and shoves a pizza slice into the "mouth". When Homer notices Bart witnessing this, he claims "I'm doing this for work."
- Misspelling Out Loud: After Bart confesses to Marge that he was the one who planted the bra:Bart: Does this mean you and dad might get a D-A-V-U-R-S?
Marge: Young man, you go work on your spelling, or I'll delete all your custom ringtones from your cell phone!
- Power of Trust: Homer trusting Marge is what helps to get them back together.
- Well, This Is Not That Trope: Lisa asks Homer where he will by staying. He asks if she knows the Four Seasons, implying he is staying in a hotel of that name. He then says he is experiencing them firsthand since he is going to live in the park.
- Zany Scheme: Lisa explains to Bart that stupid movie schemes don't work in real life. She says that their parents have a marriage on the rocks and have to work together to make sure it doesn't shatter. Bart associates the words rock and shatter with jagged cliff, giving him the idea for "the most insane, harebrained, foolproof scheme ever!"