When Bart first walks into his room, his bed sheets go all the way down to the ground. When Bart rolls under his bed they are only down a few inches.
Sherri and Terri are reading two magazines. The magazine "First Born Twin" has a picture of Patty on it. The magazine "Second Born Twin" has a picture of Selma on it. However, in "Principal Charming," Selma reveals that Patty is two minutes younger than her.
When Bart is excitedly puts his test with a full correct score on the side table, you see it for a moment close up. There are 12 states but 13 answers. The test is actually missing a state -Arkansas - between Arizona & California