Trivia: The Simpsons holds the record for most guest stars; it is also the only non-variety show to have had appearances from three former Beatles (Paul, George and Ringo).
Trivia: The only voice artists who regularly perform as only one character are Yeardley Smith as Lisa and Marcia Wallace as Edna Krabappel. Yeardley has also voiced different versions of Lisa (Lisa Jr. and Lisabella) in at least two other episodes.
Trivia: Maggie scans as $847.63 in the supermarket at the beginning (not NRA4EVER, as Troy Maclure asserts in 3F31 "The Simpsons 138th Episode Spectacular), the price it costs to feed and care for the average American baby every month.
Trivia: Many of the characters in the show are named after streets in Portland, Oregon. These include Flanders, Kearney, Lovejoy, Quimby and Terwilliger (Sideshow Bob).
Trivia: Initially, Yeardley Smith auditioned for the voice of Bart and Nancy Cartwright for the voice of Lisa. They play them the other way around.
Trivia: The salesman character Gil, who can't catch a break, is based on Jack Lemmon in Glengarry Glen Ross (1992).
Trivia: The character Professor John Frink is named after a producer of the show and based on Jerry Lewis's The Nutty Professor. Professor Frink alludes to being charged with copyright infringement in connection with Jerry Lewis at a convention.
Trivia: The substitute teacher is actually voiced by Dustin Hoffman, who is credited under a pseudonym.
Bart Gets an Elephant - S5-E17
Trivia: When Chief Wiggum is taking all the calls about the elephant and doesn't believe them, at the end of the last one he says 'Yeah right. And I'm Edward G Robinson'. Hank Azaria originally based Wiggum's voice off a bad impression of Edward G Robinson.
Trivia: Evergreen Terrace, the street the Simpsons live on, is also the street Matt Groening grew up on in Portland, Oregon.
Trivia: Homer's voice is based on the dramatic style Dan Castellaneta's father used when he talked.
Trivia: A running joke throughout the series is that no one knows where Springfield is. The writers are always coming up with ways to keep the audience guessing. Some examples of this are: in 'Sunday, Cruddy Sunday' when Marge phones the egg painting company and gives her address, she says, "742 Evergreen Terrace, Springfield Ohi...", then cuts out to say, "Oh hiya Maude!" to Maude Flanders, who suddenly appears in the kitchen. When Homer and Bart are off to the Edison Museum in 'The Wizard of Evergreen Terrace' they drive past a sign with exits to New Jersey, Michigan and Oregon, none of which are close to each other. When Larry Burns spots Mr. Burns on the train, he asks where the train is going. The conductor says, "Springfield." and Burns asks, "Springfield where?", but the conductor's reply is drowned out by the train's engine.
Trivia: In several episodes, one of Maggie's stuffed toys is a stiff-limbed rabbit. This rabbit starred in a comic strip Matt Groening used to write, about a rabbit and his journey through a troubled life. Titled "life in hell" it was renamed "life is swell" in recent years before concluding.
Trivia: Milhouse was named after Richard Milhous Nixon.
Trivia: Bart's anonymous prank calls to Moe the bartender were inspired by tapes of real-life prank calls made to New Jersey bartender Louis "Red" Deutsch (the tapes were widely circulated during the 1980s). Deutsch constantly received calls requesting fictitious bar patrons (Al Coholic, Stu Pitt, etc), and always responded in a hostile manner every time he realized he'd been duped.
Trivia: The Simpsons continually pokes fun at the Fox network because it is the only show on Fox that does not have to be checked by its executives and edited accordingly. This also means the producers of the show can get away with a lot more on prime time television.
Answer: I'm not sure if this is the one you're thinking of, but an episode of "Ray Bradbury Theatre," called "A Sound of Thunder," dealt with a similar matter: a group of hunters travel back in time to hunt dinosaurs, only to find things have changed when they get back because someone stepped on a butterfly.
Xofer