This marks the 365th episode, making it able for a different episode to air every day of the year (except in leap years, though the next episode -- "Homer's Paternity Coot" -- can be added for leap years).
This is the fourth episode of The Simpsons to date to air with a parental advisory warning before the episode in Australia for "adult themes" (most likely because of the spoof of Jesus's birth [which would have offended Christian audiences], the reference to Grampa Simpson's brother becoming a polygamist, and Moe's suicide attempts).
This episode was originally scheduled to air May 9th 2006 on Australia's Network Ten, but was pre-empted and replaced with "How I Spent My Strummer Vacation."
Homer ends his Christmas sermon with a terrible imitation of Paul Harvey.
Krusty's sidekick in 1964 bears a striking resemblance to Woody Allen, though his hairdo is very much like Sideshow Mel's.
Gabriel is a male not a female. This should be deleted because it’s not a goof, but I’ll keep it and give them simple explanation...what other character would they use as the angel?? Bart was already Jesus.