Holidays of Future Passed/References

Cultural references

 * The episode title is either a reference to The Moody Blues album ' or the Marvel Comics storyline '.
 * Homer wonders what life would be like if he never watched It's a Wonderful Life.
 * The music playing during the photo montage is "".
 * One of the ships in bottles that Homer has built is Discovery from 2001: A Space Odyssey.
 * The hotel where rock star Maggie and her band are staying is called The Benny Hilton, a reference to English comedian and the.
 * The rough-looking people flying and servicing airplanes are a nod to Mad Max.
 * During the montage of Homer and his grandsons walking around Springfield, the music playing is "" by.
 * Selma's lovebot appearance is based on in .
 * The robotic policemen seen in one shot closely resemble the from Doctor Who.
 * The Christmas-themed music during the credits is the same that is played at the end of "Treehouse of Horror XXII", the opening sequence from the episode "The Fight Before Christmas" and "Donnie Fatso" couch gag.
 * A poster in the Kwik-E-Mart advertises Soylent Green, proclaiming it to now have "30% more people!"
 * Another poster advertises "Soylent Brown".
 * The St. Beatles Cathedral is a reference to The Beatles.
 * District 9 and District 10 are a reference to the film .
 * NewTube is a parody of.
 * When Lisa goes onto the Ultranet, she notices that the logo is different and realizes that it's 's birthday. In real life, Google changes its logo to commemorate birthdays of famous people and anniversaries of other significant events.
 * The Ultranet is very similar to and may draw inspiration from Futurama's.
 * In her room on the Ultranet, Zia Simpson has a poster of Empress Zimzam, who bears a strong resemblance to from the Star Wars prequel trilogy. In particular, Zimzam's headdress is almost exactly like one that Padmé wears in .
 * In the Heathrow Teleport, a man travels to . This is most likely a reference to Futurama but there are other locations called New New York in sci-Fi shows/movies.
 * The announcer yelling "Goooooaaall!" (guest voiced by creator Matt Groening) is likely a reference to Andrés Cantor, a sportscaster who is famously known for yelling this when a team scores a goal.
 * The receptionist at the Springfield General Hospital makes references to the.

Trivia

 * This episode is a sequel to "Future-Drama". "Days of Future Future" is a sequel to this episode.
 * Originally, this episode was supposed to be the series finale, as Fox was considering cancelling the show due to money issues stemming from advertising the show. Once the issues were resolved with a pay cut for all involved with the show, the series was greenlit for season 24 and 25.
 * It's also include with The Simpsons The Complete Sixteenth Season DVD as the bonus episode in Extras menu on Disc 3 (But it cropped from original widescreen at 16:9 to fullscreen version at 4:3). With the audio language selection of and.
 * The end of this episode is a futuristic version of the end of Season 1's "Simpsons Roasting on an Open Fire".

Simpson family

 * Maggie has become a rockstar.
 * Maggie had one child.
 * Bart got married to Jenda, had two kids and got divorced.
 * Bart moved into The Lofts at Springfield Elementary.
 * Lisa got married to Milhouse Van Houten and had one child, Zia Simpson.
 * Lisa's great-great-great-great half aunt, Eliza Simpson, married Milford Van Houten at some point in her life. This means Lisa is unknowingly married to a distant relative of hers.
 * Abraham Simpson was cryogenically frozen because he had an incurable disease. Eventually a cure was found, but Abe was kept frozen because it was cheaper than putting him into a home. In the family photo album, Grampa only appears in the first photo, implying he may have gone to the cryogenics factory after the first photo and before the second.
 * Patty and Selma got Lovebots who then go off together instead.
 * Santa's Little Helper and Snowball V evolved into intelligent beings.

Springfield citizens

 * Kearney Zzyzwicz has become a taxi driver. He is also an ex-convict; he tells Maggie that he was once in prison with Bart.
 * Snake Jailbird has become a RoboCop-like cyborg.
 * Apu and the Nahasapeemapetilon Octuplets work in the Kwik-E-Mart, where they have powerful guns.
 * The Octuplets have had octuplets of their own.
 * Apu's brother Sanjay has died, and Apu believes him to have been reincarnated as a cow.
 * The hounds owned by Mr. Burns are now just bones.
 * Ralph Wiggum becomes police chief and makes a number of clones of himself. Several of these clones are seen being killed in mishaps caused by other clones.
 * Martin Prince, Jr. underwent gender reassignment and became "Marcia Princess".
 * Crazy Cat Lady, Jasper Beardsley, Gary Chalmers and Agnes Skinner are all cryogenically frozen.
 * Lenny and Carl have swapped brains.
 * Homer accidentally killed Edna Krabappel, leaving Ned to get back together with Maude Flanders.
 * From the chalk outlines on the floor of Moe's Tavern, it is evident that a number of people have died in the bar over the years. Among them are the Capital City Goofball and Sideshow Bob, the latter apparently after stepping on a rake.

Around Springfield

 * Springfield Elementary School has been converted into The Lofts at Springfield Elementary. Former principal Seymour Skinner is now the landlord.
 * Lard Lad Donuts has became the First Church of Lard Lad.
 * The Itchy & Scratchy Show still exists, but now has different theme music and is aired as a 3-D hologram.

Others

 * Earth put a man on the sun.
 * Aliens are seen living on Earth peacefully.
 * Shrink rays have been invented.
 * Martians have been discovered.
 * Cloning is accessible to people.
 * Hover cars are in common use.
 * Cryogenic freezing is accessible to freeze ill people.
 * It is now illegal to strangle one's own children, thanks to "Homer's Law".
 * has risen to power, become a ruthless tyrant and reinstated capital punishment in the form of beheading.
 * Trees are revealed to be alive.
 * The night sky is now used as advertising space, as the stars are rearranged to spell out ad slogans. Two advertisers seen using this medium are Buzz Cola and Cookie Kwan (whose slogan is now "#1 in the western sky").
 * While the Internet still exists, many people (including Zia Simpson) go online via the Ultranet, a virtual reality environment that people connect to by plugging cables into ports on their necks.
 * Teleporting is now the most common method of travel, but some medical conditions, such as pregnancy, preclude it. Also, if you talk while being teleported, people on the receiving end can hear you.
 * Bart's sons go to his apartment by teleporter. Before they arrive, Bart hears them complaining about having to spend Christmas with him.
 * In London, Maggie is denied access to the teleporter due to her pregnancy, and is forced to take an airplane flight to Springfield.
 * People can get messages sent direct to their brains, called B-Mail. Viruses sent via B-Mail can cause seizures.
 * Some people can hear thoughts. It is unknown if they hear them all the time or if it's at will.
 * Shape-changing tattoos now exist, evidently based on holograms or similar technology. Zia has one on her left upper arm.
 * Some body parts can be replaced by ordering new ones. Homer promises Marge some "future sex", meaning that it'll happen a week from tomorrow, as "That's when the new penis gets here."

Goofs

 * Lisa mentions that it's ' birthday. However, he was born on March 2, 1904 and the episode takes place just before Christmas. (It is possible, with all that has changed in the future, that Christmas is now observed in March.)
 * Even though Edna was killed, she is still able to send a friend request to Lisa on the Ultranet. (Edna could have made the friend request BEFORE she was killed, and Lisa is only now seeing the request. We're given the impression that Lisa isn't a very frequent user of the Ultranet.)
 * When Bart & Lisa get drunk, their voice actresses were actually slipping into their real voices.

Continuity

 * Homer talks about it being the future, like he did in "Bart to the Future".
 * Mr. Burns last released the hounds at Christmas in "Dude, Where's My Ranch?".
 * Bart's ex-wife Jenda was previously seen as his girlfriend in "Future-Drama", another future-set episode.
 * One of the categories on the Ultranet Facebook is "The Simpsons go to.." and shows pictures of various people the Simpsons have met when they've visited other countries:
 * Ugolin from "The Crepes of Wrath".
 * Andy and the guy with the giant boot from "Bart vs. Australia".
 * Kitenge from "Simpson Safari".
 * Tony Blair and Queen Elizabeth II from "The Regina Monologues".
 * The guy in the Toucan costume from "Blame It on Lisa".
 * The Guinness brewer from "In the Name of the Grandfather".
 * Sakatumi from "Thirty Minutes Over Tokyo".
 * Jakob from "The Greatest Story Ever D'ohed".
 * The Big Digi-Ben appears. ("Lisa's Wedding")