-- When Homer goes to the police station to get the fireworks, there is red graffiti outside that says "Bart" (this is hard to see, it is below and to the right of the "FOX" watermark, and many TV's cut it off).
-- Ned's full first name is Nedward
-- In the beginning of the episode, the imprint of Maude faced toward Ned's side of the bed, but at the end it faced away.