1. Hughes actually had an elaborate dance sequence choreographed for Matthew Broderick to perform during the “Danke Schoen/Twist and Shout” parade number (for which 10,000 actual Chicagoans showed up to watch after an announcement was made that a John Hughes movie would be shooting in the city center), but it was all scrapped because Broderick badly injured his knee filming the scene in which Ferris runs through his neighbors’ backyards.

2. The dirge-like song that Cameron sings to himself while lying in his sick bed (“Let my Cameron go”) is an old spiritual called “Go Down, Moses” credited to the Fisk Jubilee Singers in 1871. The actual lyrics were “When Israel was in Egypt’s land: Let my people go/Oppress’d so hard they could not stand, let my people go.” You can see the scene here.

3. Although they were playing high-school classmates, Mia Sara and Alan Ruck (Sloane and Cameron) were more than 10 years apart in age. Sara was 18 when she filmed the movie, while Ruck was a few months shy of his 30th birthday.

4. Ben Stein’s entire economics lecture (“Something D-O-O economics. Voodoo economics.”) was improvised. Said Stein later, “John Hughes asked me to ad-lib two scenes: One, teaching, which was something I was familiar with, and, two, taking attendance. When I finished the [teaching] scene, everyone on the set was gathered around and started applauding. I thought they were applauding because they’d learned something about economics. I later learned they were applauding because it was so boring.”

5. In 1990, a TV spin-off called simply “Ferris Bueller” debuted on NBC. It lasted less than one season, but is notable for being the first starring role for young Jennifer Aniston. (She played Jeannie.)

6. Two other last-minute edits still leave their marks on the finished film. There was supposed to be a longer sequence at Chez Quis in which the main trio marvels at the fact that the restaurant serves pancreas. Although the scene was cut, it is referenced near the end of the film when Ferris tries to convince Cameron that they had a good day, one of his examples being that “we ate pancreas.” Also, when Ferris first calls Cameron in the beginning of the movie, he is drawing a nude woman on his computer. She was supposed to end up on the Jumbotron at Wrigley Field, but the sequence was cut. One thing that was removed entirely was a scene involving Ferris telling some Chicago call-in-radio hosts that he was the first teenager launched into space by NASA. It was supposed to create a whole subplot for the film, but it was excised following the Challenger disaster in early 1986.

7. In the original version of the movie, Ferris had two younger siblings who were almost completely edited out of the final release. However, look closely during the scene early on when Ferris’ dad calls from his office to check in on Ferris. Behind him is a framed family portrait featuring more kids than just Ferris and Jeannie. It would also explain why the family had kiddy drawings so prominently displayed on the fridge. (They were actually done by Hughes’ 6-year-old son.)

8. Almost all of the license plates visible in the movie reference a John Hughes film (except for the Ferrari’s classic “NRVOUS,” which is self-explanatory). Ferris’ mom’s plates say “VCTN” (Hughes wrote the screenplay for National Lampoon’s “Vacation”), his dad’s say “MMOM” (Hughes wrote the screenplay for “Mr. Mom”), his sister’s say “TBC” (Hughes wrote and directed “The Breakfast Club”), and Mr. Rooney’s car says “4FBDO” (for “Ferris Bueller’s Day Off”).

9. The actors who played Ferris’ parents, Lyman Ward and Cindy Pickett, actually got married after filming and were together for six years before divorcing in 1992.

10. Did Chez Quis — the “snooty” French restaurant that Ferris, Cameron and Sloane B.S. their way into — look familiar? It’s a real place called L’Orangerie (located in West Hollywood, Calif., not Chicago), and it’s appeared in movies ranging from “St. Elmo’s Fire” (when Emilio Estevez brings Andie McDowell there on a date) to “Brewster’s Millions” (when Richard Pryor treats a horde of random strangers to lunch there) to “Intolerable Cruelty” (when George Clooney and Catherine Zeta-Jones’ first meeting takes place there).

Source: Mandatory.com