The Simpsons: Season 17, Episode 19
The family attends "Stab-A-Lot: The Itchy and Scratchy Musical." The musical's director is a graduate of Springfield Elementary and Principal Skinner puts his foot in mouth when he makes sexist comments about her education and that of women in general. He tries to make the situation better, but only buries himself deeper and deeper until he is fired and replaced by Women's Educational Expert Melanie Upfoot. The first thing she does is split the school into girls and the boys. Lisa dislikes the way girls are being taught math and she ventures over to the boy's side of the school in search of a challenge. Disguising herself as Jake Boyman she starts attending the boy's school but while she finds the math problems more interesting, it is being a boy that is a greater challenge.