If you look carefully at the janitor elf, you'll see he's smoking a candy cane.
When Brain opens the French cookbook, the first two foods seen are French Toast and French Fries. Ironically, neither food originated in France; French Toast is believed to have been created in Italy, while French Fries are an American creation.
The pigeons on the Justice of the Peace statue outside the courthouse are the Goodfeathers characters from Animaniacs.
The size and shape of the hole in the boss's desk changes back and forth.
Pinky's catch phrase "Narf" stands for Nuclear Attack Readiness Formation. At least... it does in this episode.