In Trading Places, millionaires Randolph and Mortimer Duke can't agree on the whole nature versus nurture theory. So they decide to bet $1 on it and determine the winner by installing homeless con artist Billy Ray Valentine (Eddie Murphy) in the old job at their firm held by Louis Winthorpe III (Dan Aykroyd), who was set up to lose everything by the Duke brothers. When the two find out about the bet, they seek revenge.

1. THE IDEA WAS INSPIRED BY A TENNIS GAME.

"There were these two brothers who were both doctors who I would play tennis with on a fairly regular basis, and they were incredibly irritating to play with because they had a major sibling rivalry going, all the time about everything," screenwriter Timothy Harris explained. He presented the idea of brothers arguing the nature versus nurture debate to his writing partner, Herschel Weingrod, and the two went to work.

2. THE SCREENWRITERS HUNG OUT WITH DRUNK TRADERS FOR THEIR RESEARCH.

"The traders I met and hung out with here in L.A., because it was three hours behind New York, had their happy-hours very early in the day," Weingrod explained to NPR. "You can imagine what they were like by, maybe, 2 p.m."

3. IT WAS ORIGINALLY A RICHARD PRYOR/GENE WILDER VEHICLE TITLED BLACK AND WHITE.

Richard Pryor was originally attached, but as director John Landis put it, he then "unfortunately set himself on fire."

4. LANDIS DIDN'T KNOW WHO EDDIE MURPHY WAS.

"48 Hrs. (1982) hadn't come out yet, but they'd previewed it, and Eddie Murphy had previewed very well, and they thought, 'Ah this kid's going to be a star,'" Landis recalled of his discussions with Paramount Pictures. "So they said, ‘What do you think about Eddie Murphy playing the Billy Ray Valentine part?’ And I of course said, ‘Who’s Eddie Murphy?’"

Ralph Bellamy, who played Randolph Duke, remembered a moment on set between himself, Don Ameche (who played his brother, Mortimer Duke), and Murphy in the makeup trailer on the first morning of shooting. "I said, 'Why, this is my 72nd movie.' And Don answers, 'Why, this is my 56th.' And Eddie Murphy looks embarrassed and said, 'Boys, this is my first. Ever.' It broke everybody up, and the movie became my biggest hit."

5. LANDIS THOUGHT DON AMECHE WAS DEAD.

Ray Milland (Dial M for Murder) was originally cast as Mortimer, but he didn't pass the insurance physical. When Landis asked for Don Ameche, he was informed that he had not made a movie in 13 years and he couldn't be found. "The horrible question was asked, 'Did he die?'" Landis remembered. Ameche was found, and held off on agreeing to return to movies until he was paid what Milland had been promised. Two years after Trading Places, Ameche starred in Cocoon (1985) and won an Oscar for his efforts.

6. THE CO-STARS WEREN'T FAMILIAR WITH EACH OTHERS' WORK.

Bellamy and Ameche "cheerfully admitted" they were unfamiliar with Murphy and Aykroyd's work. The two also said that Murphy and Aykroyd acknowledged that they were unfamiliar with Bellamy and Ameche.

7. JAMIE LEE CURTIS WAS A HARD SELL TO THE STUDIO.

When it came to casting, Landis said, "What really got me in trouble was Jamie Lee Curtis, because up to that point she had only done horror pictures. But Jamie did a terrific job. She somehow made her part, the hooker with a heart of gold, almost believable!"

8. G. GORDON LIDDY ALMOST AGREED TO PLAY CLARENCE BEEKS.

The role eventually went to Paul Gleason (The Breakfast Club) instead, after G. Gordon Liddy allegedly considered playing Clarence until reading the final scene involving his character getting sexually assaulted by a gorilla. In the movie, Beeks reads Liddy's autobiography Will on the train.

9. IT WAS SHOT IN PHILADELPHIA, NEW YORK, AND ON THE U.S. VIRGIN ISLANDS.

Fifteen days of exterior shooting took place in Philadelphia. The city was chosen by Harris because it "has a connection with the founding of the country, the constitution, everybody being entitled to the pursuit of happiness, all the idealism that’s built into America." But the interiors of the Duke & Duke office and other Philadelphia locations were shot in New York City. On the last day of production, March 1, 1983, filming concluded on a beach in the U.S. Virgin Islands.

10. JAMIE LEE CURTIS STAYED IN MARLENE DIETRICH'S PARK AVENUE APARTMENT DURING THE SHOOT.

She was engaged to Marlene Dietrich's grandson, production designer J. Michael Riva, at the time. It was located at 993 Park Avenue.

11. BREAKING BAD'S GUS FRING WAS ONE OF EDDIE MURPHY'S CELLMATES.

Giancarlo Esposito portrayed "Cellmate #2." "I was in awe of Eddie Murphy," Esposito admitted. "At that time, I was probably a little jealous of Eddie Murphy. Because you work all your early career to be a dramatic actor, and then this guy, a comedian with an affable personality who’s incredibly talented, just shoots right by you to stardom. But that day, we became friends."

12. THERE WERE OTHER INTERESTING CAMEOS.

Bo Diddley played a pawnbroker, Jim Belushi was in the gorilla costume, Al Franken and Tom Davis played baggage handlers, Frank Oz played a police officer, and Kelly Curtis, Jamie Lee's sister, played "Muffy."

13. AL FRANKEN STILL GETS PAID FOR HIS CAMEO.

In releasing his financial records for 2012, Al Franken revealed he still gets royalties for his appearance as the baggage handler.

14. AYKROYD AND MURPHY CAUSED BILLIONS OF DOLLARS IN TRADING TO STOP.

Initially, in a shoot where real stock traders performed with some extras at the World Trade Center's commodity exchange, Comex, Aykroyd and Murphy were supposed to perform on a weekday during actual trading. According to the studio production notes, the two stars distracted business activities and $6 billion of trading was halted. They then rescheduled to film over the weekend.

15. BASED ON THE ENDING OF THE MOVIE, THE COMMODITY FUTURES TRADING COMMISSION INSTALLED AN "EDDIE MURPHY RULE" IN 2010.

In 2010, the banning of using misappropriated government information for commodity markets trading was still not technically illegal. The "Eddie Murphy Rule" went into effect as part of the Wall Street Transparency and Accountability Act of the Dodd-Frank Wall Street Reform and Consumer Protection Act. In Trading Places, the Duke brothers used insider info from a not-yet-released USDA report that said orange crops are lowering in value to buy frozen concentrate orange juice futures. The problem for them was that Aykroyd and Murphy wrote the fake report.