When shopping with Clark, Eddie asks Clark if it was his company that "killed all those people in India". He is referencing the Bhopal disaster, also known as the Union Carbide disaster, in which leaks from a Union Carbide pesticide plant escaped into the air. Thousands of people died, and many more were sickened.
The movie is based on John Hughes' short story "Christmas '59", the second Vacation story to be published in National Lampoon's Magazine (the first was "Vacation '58", which was the basis for National Lampoon's Vacation (1983)). The Christmas story was printed in December 1980. The label on the home movie reel that Clark finds in the attic is labeled "Xmas '59," a further allusion.
According to an article on the making of Home Alone (1990) in Chicago Magazine, Chris Columbus states that he was the original director of this movie. Although he filmed some second unit establishing shots (which he claims are still in the finished film), he left after two meetings with Chevy Chase, and told Writer and Producer John Hughes, "There's no way I can do this movie. I know I need to work, but I can't do it with this guy." He was sent the script to Home Alone (1990) in its place.
After Clark Griswold unsuccessfully attempts to demonstrate his handiwork with the house Christmas lights to his family, he asks Rusty to help him check all the light bulbs again. Rusty looks at his bare wrist, pretending to have a watch, and excuses himself. Looking at a bare wrist and pretending to have a watch, is one of Chevy Chase's trademark gags.
The house in which the Griswolds' neighbors, Todd and Margo, live, is the same house where the Murtaugh family lived in all four Lethal Weapon movies (1987-98). The houses on this street are on the Warner Brothers backlot. Ironically, in each Griswold "Vacation" movie, Rusty and Audrey are played by a different actor and actress, while in all four "Lethal Weapon" movies, the three Murtaugh kids were played by the same actor and actresses. Speaking of Danny Glover movies, two "Christmas Vacation" stars have immediate family who appeared in movies with Danny Glover. Juliette Lewis' father Geoffrey Lewis appeared in the Mel Gibson movie Maverick (1994), during the Danny Glover cameo. Randy Quaid's brother Dennis Quaid starred with Glover in Switchback (1997).
According to Randy Quaid, many of cousin Eddie's characteristics (most notably the clicking of the tongue) were based off a guy that Quaid knew, from when he grew up in Texas years ago, who had similar traits.
Near the end of the film, Rusty says, "I told you we should have gone to Hawaii!" In the first National Lampoon's Vacation (1983), when asked where in the world he would like to go the most, Rusty said Hawaii.
After failing to get the Christmas lights to work one last time, Clark Griswold takes his frustration out on the plastic decorations in the front yard. Chevy Chase actually broke his pinky finger while punching Santa Claus. He resorts to kicking and clubbing the decorations after that. The film kept rolling, and the take was used.
When Clark and Cousin Eddie are talking in the living room, they are drinking egg nog out of Walley World mugs. Walley World was the destination of the Griswold's in National Lampoon's Vacation (1983).
Cousin Eddie explains to Clark that his older kids couldn't make it because his daughter was "at the Clinic getting cured off the Wild Turkey" and his son was preparing for his career as a carnival worker. This is a reference to Cousin Vicky and Cousin Dale from National Lampoon's Vacation (1983). Cousin Vicky would return once again in the following film, Vegas Vacation (1997), as well as Ruby Sue from this film (though played by a different actress).
When Cousin Eddie barges into the house with Clark's boss, Ellen jokingly tells him this is the family's first kidnapping, which is actually wrong. In National Lampoon's Vacation (1983), Clark holds the security guard at Walley World hostage, and forces him to take the family on the rides.
The Warner Brothers backlot used for the neighborhood, in which the Griswolds live, is the same as the one used on The Middle (2009), which featured Brian Doyle-Murray (Mr. Shirley) in a recurring role as Mr. Ehlert, and Doris Roberts (Frances) in a recurring role as Ms. Rinsky.
When Clark and Ellen discuss their concerns over Eddie and Catherine not having any Christmas presents for their kids, Ellen says that Eddie has "been out of work for close to seven years." In National Lampoon's Vacation (1983), Eddie mentions having been laid off from an asbestos factory, which would have been nearly seven years before this movie takes place.
Just before Clark gets locked up in the attic, he pulls out an old present from a hidden slot, and it contains a card that reads "Happy Mother's Day 1983, Love Clark". The first movie, National Lampoon's Vacation (1983) was released that same year.
Brian Doyle-Murray appears in two of the Vacation movies. In this one, he played Frank Shirley, Clark's boss. In the first one, he played the Kamp Komfort clerk, where the Griswolds stop to stay on their way to Walley World.
John Hughes was asked if he wanted to write a new film for the Vacation franchise. He said he would only do it if he had a good story to use, as by this point, the franchise was a Chevy Chase vehicle, and there was little need for him to write a story. He found one called "Christmas '59" from his time working at National Lampoon Magazine that he thought was good, so he agreed to write the script.
All the presents that are on the credenza when Clark goes in to give his to Mr. Shirley, are identically shaped, and likely the same gift. It is a desk organizer. When this movie came out, pen sets came in an L-shaped arrangement. The writing instruments were on the flat part, and the raised section held Post-It notes. Paper clips and other holders were also a possibility.
A Walmart storefront appears in the film, with an empty parking lot. At the time of the film's release, Walmart did not have their stores operating twenty-four hours a day, and many still don't. This began when the chain was remodelled a few years later, and the company converted their stores to Supercenters (similar to its Sam's Wholesale Club stores without the annual membership fees). In real-life, the slang for Walmart is "Wally World" (appropriating the name of the Walley World theme park from the first film, when referring to a box retailer).
When the grandparents arrive at the Griswolds' house, Frances says to Ellen, "Doesn't Nora look old?" Diane Ladd was only fifty-three years old when she played Nora Griswold in this film. The film was released in theaters only two days after Diane Ladd's fifty-fourth birthday.
In several outdoor scenes at the Griswold house, a 1963 powder blue Lincoln Continental convertible can be seen parked out front. This was the last of the curved glass slab sides, and is sought after by collectors. The 1964 Continental convertible had straight glass windows to provide more interior space.
When Clark has the tirade and says, "We're gonna have the hap hap happiest Christmas since Bing Crosby tap danced with Danny f***king Kaye!" This was a nod to a scene from White Christmas (1954), and the quote was the second one in a 1980s PG-rated movie to feature the "f" word and have it be uncensored, considering Big (1988) also had the "f" word spoken by one of its characters, and have it be uncensored.
The messenger, who delivers Clark's Christmas "bonus", is wearing a jacket that reads "Speed Ball Messenger Service". "Speedball" is a street term for a drug cocktail of heroin and cocaine, the same mixture that killed John Belushi.
When Clark shows his co-worker Bill (Sam McMurry) the brochure about the swimming pool he wants to put in his backyard, he is seen drinking coffee out of a Tasmanian Devil coffee mug. Miriam Flynn (Cousin Catherine) would later go on to play the voice of Taz's mother in the cartoon Taz-Mania (1991). Additionally, Taz's father in that cartoon, was a parody of Bing Crosby, whose song "Mele Kalikimaka" appears in this film, and whom Griswold mentions along White Christmas (1954). Furthermore, John Astin, who played game show host Kent Winkdale in National Lampoon's European Vacation (1985), was the voice of Bull Gator on that cartoon.
In addition to Randy Quaid and Natalija Nogulich having the same date of birth, there are several other notable birthday coincidences among the cast. Nogulich was born on the first of October, while her on-screen husband, Brian Doyle-Murray, was born on the last day of October. E.G. Marshall and John Randolph, who play Ellen's father and Clark's father, respectively, were both born in the month of June. Doris Roberts and Diane Ladd, who play Ellen's mother and Clark's mother, respectively, were both born in the month of November. Mae Questel and William Hickey, who play Aunt Bethany and Uncle Lewis, were both born in the month of September. Marshall and Miriam Flynn were both born on June 18.
When Clark and Cousin Eddie talk about Eddie's children, Eddie calls the Tilt-a-Whirl ride the "Tilty-Whirl," a mistake quite in line with his rather simple-minded personality. A common slang name for the Tilt-a-Whirl is the "Whirl and Hurl."
Brian Doyle-Murray and Natalija Nogulich, who play husband and wife in this film, are the only natives of Chicago, Illinois (where the movie is set, even though it was filmed in California, Colorado, and Chicago, Illinois) among the film's cast. All other cast members were born outside Illinois. They both guest starred in season three of 2 Broke Girls (2011).
The trivia items below may give away important plot points.
The scene where the cat bites on the Christmas lights cord and gets electrocuted was nearly cut from the movie. Prior to the first test screening, the studio executives wanted the scene taken out, fearing that it might offend some viewers, but Producer Matty Simmons begged them to leave the scene in, and they eventually gave in to his request. After the first test screening, the test audience scored the cat electrocution scene as their number one favorite scene throughout the entire movie.