You might know that National Lampoon’s Christmas Vacation was written by John Hughes, the guy behind ’80s classics like The Breakfast Club and Ferris Bueller’s Day Off. But did you know that before Hughes became a filmmaker he was a contributor to the National Lampoon magazine? In fact, he based his Christmas Vacation screenplay on one of his old Lampoon pieces, “Christmas ’59.” That’s just one of the jolly facts featured in the newest episode of You Think You Know Movies!

As fun as the Vacation series is, continuity is not its strong suit. In the previous two movies, Rusty was the older brother of the Griswold clan. In Christmas Vacation he not only is played by a new actor (future Big Bang Theory star Johnny Galecki), he also seems to have become younger than his sister Audrey. In the film, Ellen Griswold also claims that this is the Griswolds’ first kidnapping. But Vacation fans remember that they also kidnapped the security guard at Wally World in the original film.

‘You Think You Know Movies?’ is a ScreenCrush original series that dives deep into the cinematic worlds of your favorite movies and freeze frames a few tidbits you might not have known. We’ve already tackled Star Wars, The Avengers and Spider-Man, but this time we’re heading home for the holidays and some Christmas Vacation facts. Watch more installments of ‘You Think You Know Movies?’ below and let us know in the comments what movies we should cover next.

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