"That '90s Show" is the eleventh episode of The Simpsons' nineteenth season. It first aired on the Fox network in the United States on January 27, 2008. Kurt Loder and "Weird Al" Yankovic both guest star as themselves, this being the second time for Yankovic. The episode was written by Matt Selman, and directed by Mark Kirkland.
After Bart and Lisa discover Marge's degree from Springfield University, Homer and Marge recount one of the darkest points of their relationship. The episode significantly retcons some of the Simpson family history, depicting the timeframe of Homer and Marge's romance as being in the 1990s due to the show's long run, as opposed to the mid-late 1970s and early 1980s setting in the early episodes, though later episodes would return to the latter setting.
The Simpson family are suffering inside their freezing house because Homer (counting on global warming) didn't pay the electric bill. Bart and Lisa, searching for items to feed the fire, discover a box containing a degree belonging to Marge from Springfield University. Homer and Marge look shocked to find it, and claim it was from their dating years. Lisa does some calculations and realizes that, because Bart is 10, and Homer and Marge are in their mid-to-late thirties, Bart must have been born later in their parents' relationship than they thought. Marge and Homer proceed to describe one of the darker points of their relationship, the 1990s.
In the flashback, Homer and Marge are happily dating, living together in an apartment. Marge is an avid reader, and Homer is part of an R&B group alongside Lenny, Carl, and Officer Lou. One morning, Marge wakes up to find out she had been accepted into Springfield University, but is shocked to learn of the high cost of tuition. Homer, taking pity on Marge, gives up his dream of becoming a musician and instead decides to work at his father's popular laser tag warehouse in order to pay for it, where he is abused by the children. At Springfield University, Marge is impressed with her surroundings and with the radically feminist revisionist history professor Stefane August, despite Homer's disapproval.
Marge soon begins to admire August, and realizes she has feelings for him. August begins manipulating Marge by telling her Homer is a simple "townie" who would not appreciate her intellect. A shocked Homer arrives and catches the two together. In his anger, he reforms his R&B group with a new sound called "grunge," which Homer explains is an acronym for "Guitar Rock Utilizing Nihilist Grunge Energy." His band is renamed to "Sadgasm" and they sing a song Homer calls "Politically Incorrect" (based on "Frances Farmer Will Have Her Revenge On Seattle" and “Heart Shaped Box” by Nirvana), listed in the episode's credits as "Kisses are Dirt". An angry Marge and Homer soon call their relationship quits, and Marge leaves to go with Professor August.