This episode's production code (SABF13) can be seen on Bart's Moving On profile.
Goof: When the older Milhouse is first seen 35 years in the future, shots alternate from him having gray hair to having blue hair.
Show Title: Martin Prince hanging with his underwear on a flagpole as a three-eyed crow flies by.
Billboard and Chalkboard Gags: None.
Couch Gag: When the Simpsons arrive, the floor and couch are covered in bubble wrap, and they can't resist popping it on the floor by jumping and stomping all over it. After they sit on the couch, Homer pops the last unpopped piece on the floor by reaching over with his foot
The title of this episode is a pun on the X-Men tale Days of Future Past, first seen in Marvel Comics, then the 1990's animated TV series, and soon, the Marvel Studios movie featuring the mutant heroes and villains.