The family goes to the YMCA to attend one-time-only free classes, along with many other Springfieldians who admit they will never return to the YMCA and pay for any of the regular classes. Lisa takes gymnastics (and gets yelled at by the Russian coach for being too old), Bart gets tricked into taking an etiquette class by a black man dressed as a gangsta rapper (who happens to be the husband of the prim and proper etiquette teacher), and Homer participates in a basketball class for men over the age of 35, but suffers a torn ACL after a dunk attempt ends with the backboard crashing down on his leg. After Homer gets his surgery, he is told by Dr. Hibbert that he cannot go to work, and he must stay home. Homer finds himself extremely bored, even going so far as attempting to cross-breed Santa's Little Helper and Snowball II. One evening, Ned wants Marge to watch Rod and Todd while he attends a Chris Rock concert (that he misinterprets to be an abbreviation for a christian rock concert and after is surprised by the language), but Marge is out identifying the body of her Uncle Lou (which ends up being a very much alive Hans Moleman, although the morgue attendant seems convinced that he is dead) so Ned asks Homer instead. The kids like having Homer take care of them, which allows Homer to establish his own day care center.
Homer starts a day care center (under Marge's ownership), "Uncle Homer's Day Care Center", to entertain himself, but makes Bart and Lisa feel like outcasts by ignoring them, giving Bart's jacket to Milhouse, forcing them out of their bedrooms for a film crew that is making a documentary about him, and having them work long hours at night to cut out felt hearts in his honor. The daycare center is wildly successful, and Homer earns a nomination for the "Good Guy Awards" ceremony. For the ceremony, Bart and Lisa splice in home movie footage of Homer at his worst (passed out on the floor drunk and almost naked during Christmas, losing Maggie in a poker game, and chasing Bart down the street while wielding a flail) to prove to everyone that Homer is a bad father and a worse person. The audience becomes outraged and Homer angrily strangles Bart on stage. Everyone in the audience becomes horrified by Homer's behavior, and decide to prevent their kids from being watched over by him. Homer escapes from the ceremony with all the kids in a van, until he crashes the van into a tree, and tries to escape before Chief Wiggum stops him. After three mistrials, Homer apologizes to Bart and Lisa for neglecting them, and promises to care for his own children (including the perpetually ignored Maggie) instead of the neighborhood kids. The family then helps themselves to the craft table, which the teamsters left behind in their house but are supposedly picking up later that day.