Actor Allusion: Ferris hacks into his school's computer to improve his record... just as David Lightman did in WarGames.
All There in the Script: Charlie Sheen's stoner character is named Garth Volbeck, though the film doesn't mention this.
Also, a deleted backstory shows that Ferris and Garth were friends in the eighth grade. Garth's family's pretty messed up, and Ferris tried to help him and be his friend, but Garth eventually dropped out of high school and wound up in the police station next to Jeannie. That's why Ferris is so intent on giving Cameron a good time - he blames himself for not helping Garth enough when he could.
Cast Incest: On-screen siblings Matthew Broderick and Jennifer Grey dated and were even engaged for a while after appearing in this film together.
Dawson Casting: Averted with Mia Sara, (Sloane) who was 18 (playing a high school junior). Played straight with Matthew Broderick (Ferris) who was 23, Jennifer Grey (Jeannie) who was 25, and Alan Ruck (Cameron) who was 29 when the film was shot during the fall of 1985.
Flip Flop of God: The DVD commentary pegs Ferris as a spoiled jerk. However, Hughes intentionally cut a scene that explicitly makes Ferris a thief, and cast Matthew Broderick in the role because he felt Broderick was the only one who could make Ferris likable. So do we empathize with Ferris or not? Either interpretation of the character is equally valid. And it doesn't help that both interpretations can work concurrently with each other (i.e. Ferris is a jerk and trickster, but he's OUR jerk and trickster).
Hey, It's That Guy!: Ben Stein plays the dull, drab teacher whose class Ferris escapes from at the beginning of the film. He would later rehash this role on The Wonder Years, among many other places.
Also Actor Allusion for Ben Stein, as he was a political commentator and speech writer, who wrote and spoke at length about economics, just as he taught in this film. In fact, he wasn't even given lines for his lecture scenes; he was just told to deliver a lecture on something he knew a lot about.
Real-Life Relative: The actors who played Ferris's parents (Cindy Pickett and Lyman Ward) later got married in real life. Unfortunately, however, they divorced in 1992.
Throw It In: "They think he's a righteous dude" was improvised by Edie McClurg, the actress who played Grace.
Ben Stein improvised the entire lecture about the Hawley-Smoot Tariff.
What Could Have Been: John Hughes' first choice to play Ferris was Michael J. Fox, which is ironic because Broderick was Gary David Goldberg's first choice to play Fox's role of Alex P. Keaton in Family Ties. However, Broderick declined, partially because his father, James Broderick, had become terminally ill, and partially because he did not actually want to commit to a weekly TV series. Even more ironically, James Broderick had co-starred with Fox's Family Ties co-star, Meredith Baxter-Birney, on the ABC drama, Family.
The Hero car was built by Mark Goyette and leased to Paramount for filming. This one was used in almost all exterior shots, and is the one that jumps over the camera. When filming was completed, it was returned to Mark, with the exhaust crushed and the rear body panels cracked. He repaired it and sold it to a young couple in California. The husband ran it off the road, and Mark rebuilt the front end. The couple later sold it in the '90s, and it resurfaced in the early 2000s, but hasn't emerged again since.
A kit was sold to Paramount for their stunt car, but they did such a poor job assembling it that it was unusable for anything but falling out the window of Cameron's house at the end. It was later rebuilt and ended up in Planet Hollywood Minneapolis, but fell off the map along with Planet Hollywood Minneapolis.
A third kit, meant to be a shell to be dropped out of the window, was bought but never completed. Mark Goyette mentions he heard it was completed and sold off, but it could just as likely be sitting in a backlot at Paramount.