One of the better Treehouses in a while. The Zombie Apocalypse in particular is one of the funnier bits the show's done in a long time. For this year:
Act I: Bart and Lisa agree to "solve" each other's teacher problem. CRISS-CROSS! Act II: Krusty's mad cow burger brings about the Zombie Apocalypse. Act III: Homer impales himself on Moe's brewer, giving blood-soaked beer an aphrodisiac effect on Marge.
The "CRISS-CROSS" stuff was pretty good, especially once Willie got in on it. The idea that the last act was done in a theater setting was a neat one in theory, but didn't quite lead to as much funny as I thought it would. Overall, a decent romp, as is normally the case with Treehouse.