1. Originally, creator Matt Groening was going to pitch a series of his "Life in Hell" comic strip before realizing he would have to give up his publishing rights. He thought up "The Simpsons" in the lobby of James L. Brooks' office. There have been numerous references to "Life in Hell" in "The Simpsons," from Binky dolls to pictures of Akbar & Jeff.

2. Groening's parents' names are Homer and Margaret, and his sisters are Lisa and Maggie. He has said that his older brother, Mark, is the inspiration for Bart.

3. The Simpson family first appeared in shorts in "The Tracey Ullman Show" on April 19, 1987. It then debuted as a series on Dec. 17, 1989, becoming the first animated prime-time series since "The Flintstones."

4. Why were the characters yellow? Former director David Silverman said in 1998: "I think [Gyorgi Peluci, color stylist] made the Simpsons yellow because Bart, Lisa and Maggie don't have a hairline, so they had to be yellow, otherwise Bart would look like he had a serrated forehead if it was flesh-colored. And if they're yellow, you kind of get used to the fact that it's their hair and their skin color, once the shock wears off."

5. President George H.W. Bush said early on in the show's run, "We're going to strengthen the American family to make them more like the Waltons and less like the Simpsons." That's funny -- even presidents can be wrong.

6. Springfield, where? There are 121 Springfields in America. The Simpsons' state has never been identified (though there was once a reference to Kentucky). Groening has said Springfield resembles Portland, Ore., where he grew up. Springfield, Vt., beat out 13 other Springfield cities to host the movie's premiere.

7. Homer's famous "D'oh" is a shortened version of an expression by Jim Finlayson from the Laurel and Hardy films. Other show expressions include "Ay, caramba!," "Don't have a cow, man!" and "Eat my shorts!" (Bart); "Excellent ..." (Mr. Burns); and "HA-ha!" (Nelson Muntz).

8. Groening's favorite episode is "Bart the Daredevil," the season 2 show when Bart promises to jump the gorge, but Homer ends up in the ambulance.

9. No Doubt keyboardist Eric Stefani (Gwen's brother) left the band in 1994 to become an animator for the show. No Doubt became a hit a year later, and was seen in the Homerpalooza episode. As for the animation, the show began with traditional cel animation but switched to digital ink and paint for season 13.

10. The main voices are handled by seven actors. Groening does the voice of Maggie's bottle-sucking.

11. The very first musical guest to appear on the show was Tony Bennett in season 2. Among the notables have been three Beatles (Ringo, Paul and George), Michael Jackson, Aerosmith, the Red Hot Chili Peppers, The Ramones, James Brown, Peter Frampton, Smashing Pumpkins, Sonic Youth, Hank Williams Jr., U2, Elton John, The B-52's, Britney Spears, The Who, R.E.M., 'N Sync, Mick and Keith, Elvis Costello, Little Richard and Blink 182.

12. It costs approximately $1 million and takes six months to produce a "Simpsons" episode. (Needless to say, many are in the works at once.)

13. The show has won 23 Emmys. Harry Shearer -- who voices Mr. Burns, Principal Skinner and others -- is the only main cast member to have not won an Emmy for Outstanding Voice-Over Performance. It was nominated last week Outstanding Animated Program along with "Avatar," "Robot Chicken," "South Park" and "SpongeBob SquarePants."

14. "The Simpsons" got its star on the Hollywood Walk of Fame on Jan. 14, 2000, and The Simpsons Ride will open at Universal Studios Orlando and Universal Studios Hollywood next spring.

15. "Simpsons" special editions of popular board games include Scrabble, Monopoly, Clue, Operation and The Game of Life.

16. On jumptheshark.com, "The Simpsons" is No. 4 on the voted list of shows that "Never Jumped," behind "Lost," "Supernatural" and "House."

17. Time magazine named it the best television series of the 20th century in 1999 and made Bart one of the most influential people of the century.

18. At 18 years and 400 episodes, it is the longest-running sitcom in television history. It passed "The Adventures of Ozzie and Harriet" in 2004. This fall, it will be only one season behind the prime-time, scripted TV record of 20 produced seasons. Look out, "Gunsmoke."