When Homer goes into Bart's room after the EMP burst Bart and Milhouse are playing the board game Satan's Path from Treehouse of Horror XXI.
When Bart asks what would they do if his ear was sent by kidnappers actually happened to J P Getty III in 1973 - forty years before. It has been in America's cultural psyche ever since. (J. P. Getty III died two years before)
The conspiracy theorists consist of Superintendent Chalmers, Lindsey Nagel, Herman and Lieutenant Smash, the nutcase Naval recruiter from the episode 'New Kids on the Blecch'.
Rainier Wolfcastle's nose is briefly different to its usual appearance. His first few frames has him sporting a 'Nelson-style' nose but when he appears later on it's back to his regular nose.
6 minutes into the episode Homer leaves home and is approached by Ned but when he retreats back into the house the front door is hinged on the opposite side.