Larry Littlejunk's last name was originally Slimp.
Kenan Thompson and Will Forte record their voice parts in New York, separate from the rest of the cast, as they are members of Saturday Night Live (1975).
The American version of the Australian Sit Down, Shut Up (2000). This version was slammed by critics, it also wasn't the last time a classic Australian TV show was made into an American sitcom.
The "interpreter" joke where Happy's character says something in his native language while a British-sounding narrator says the opposite thing. According to Mitchell Hurwitz that was a joke that the Fox studio heads didn't get.