The Monkey Suit

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 trial, a la Inherit the Wind.