When Maggie gets chicken pox, Flanders tells Homer to create a pox party at the Simpson's house. But, Milhouse then finds Kirk and Luann kissing on Marge and Homer's bed. Milhouse is excited that his parents are back together, but kind of not when they're not paying any attention to him and tries to break them up with Bart. The results end up disastrous as it breaks up Homer and Marge too and then, when Bart ends up doing something, the only thing that matters to Homer and Marge is each other.
Springfield Elementary is divided into two separate schools (one for boys, one for girls) following Principal Skinner's demotion. Concerned that the boys are receiving a higher standard of education, Lisa disguises herself as a boy.
After seeing a museum exhibit on evolution, in which creation is labeled a myth, an outraged Ned Flanders teams with Reverend Lovejoy to blackmail Principal Skinner into requiring creationism to be taught in classrooms, eventually at the expense of any mention of evolution. Lisa becomes outraged herself, and forms a student organization to teach evolution, leading to a creationism vs. evolution trail, a la Inherit the Wind.