* ActorAllusion: When blood starts squirting out of Monty Python member Eric Idle's hand, he insists it's [[Film/MontyPythonAndTheHolyGrail just a flesh wound]].
** The police officer that pulls the Griswolds after dragging the dog is Deputy Halik from ''MovingViolations''.
** Cousin Eddie's daughter is a very young Jenna from ''Series/ThirtyRock''.
** [[AmericanPie Mr. Levenstein]] sells Clark the Family Truckster.
** ''European Vacation'' is filled with this for European audiences, as the supporting cast was drawn from comic and character actors from each country featured. Just to name a few: British comic actors Mel Smith (the London hotelier), Robbie Coltrane, Maureen Lipman (other guests in the hotel), Ballard Berkeley (the second motorist), and Creator/EricIdle (the injury-prone cyclist), French character performers Didier Pain (the camera thief) and Victor Lanoux (one of Ellen's kidnappers), and German comedy veterans Willy Millowitsch and Erika Wackernagel (the Griswolds' unwitting German hosts).
*** Meanwhile, for American audiences, ''Pig in a Poke'' is presented by [[Series/TheAddamsFamily John Astin]] and announced by [[Series/RowanAndMartinsLaughIn Gary Owens]].
** After ''Christmas Vacation'', Rusty will move to California and become a [[Series/TheBigBangTheory physicist]], and Audrey will become [[Film/NaturalBornKillers a serial killer.]] In addition, the parade host is played by [[Series/ThePeoplesCourt Doug Llewelyn]].
** The Kamp Komfort clerk is [[TheMarvelousMisadventuresOfFlapjack Captain K'nuckles]] and the mayor of Punxsutawney, PA and um... [[YouLookFamiliar Clark's boss]] in ''Christmas Vacation''.
* TheOtherDarrin: While Chevy Chase and Beverly D'Angelo kept reprising their roles as the Griswold parents for the first four films, their kids were played by different actors each time: Anthony Michael Hall, Jason Lively, Johnny Galecki and Ethan Embry played Rusty while Dana Barron, Dana Hill, Juliette Lewis and Marisol Nichols played Audrey. Dana Barron is the only one to return to the role; she plays Audrey in the Cousin Eddie Christmas sequel.
* PlayingAgainstType: Imogene Coca (the actress who played Aunt Edna) [[MeanCharacterNiceActor couldn't believe how mean she had to be]].
* RealLifeRelative: Harold Ramis' actual daughter Violet has a small part as Daisy Mabel, Cousin Eddie's youngest daughter who was born with no tongue.
** Today, finding out if the park is closed would be as simple as checking its web page, and because of the prevalence of GPS, getting lost driving across the country would be much more difficult.
** Also, Clark's payment problems after he's strongarmed out of his cash would not be that much of a problem nowadays considering that debit payments from his bank account is common and credit cards are accepted in far more places now.
* ThrowItIn: In ''European Vacation'', as they're checking into a hotel, Clark accidentally refers to both Rusty and Audrey as his "daughters". This was a mistake on Chevy Chase's part, but was left in because it was so Clark Griswald-ish. If you watch closely, Chase has an OhCrap expression afterward, but then shrugs it off [[TheShowMustGoOn and continues the scene]].
** The Griswold's destination was originally supposed to be Disneyland, as it was in the short story, but it was rejected since the park is open year-round and thus the ending with John Candy wouldn't have worked.
** The ending was originally completely different. Clark would hold up Roy Walley in his home and force him to sing and dance, and the police arrive to arrest Clark, when it's revealed that the mysterious woman in the red car is actually Roy's daughter. She convinces her father to drop the charges and the family goes on a flight back home after receiving Walley World hats, but they discover that they caught the wrong flight and Clark forces the pilot to turn the plane around. Negative test screenings made the filmmakers rewrite the scene.