How 'The Simpsons' Has Stayed on Top

March 8 -- "Marge, cartoons don't have any deep meaning," Homer Simpson tells his wife. "They're just stupid drawings that give you a cheap laugh," he explains, his rear end exposed above his pants.

And yet, The Simpsons, an animated sitcom, has been on the air for 13 years, achieving a rare combination of cult status and mainstream popularity. It is the longest-running sitcom currently on the air.

How has an irreverent cartoon managed to stay on top in the turbulent world of prime-time television? 20/20's Chris Cuomo went behind the scenes — and into the Simpsons' animated home — to find out what makes the show's characters and creators tick.

Nothing Is Off Limits

Back in 1992, when President George H.W. Bush was running for re-election, he used the show's characters as an example of a dysfunctional household with poor values. He told voters he wanted "to make American families a lot more like the Waltons and a lot less like the Simpsons."

It's rare that a cartoon evokes such passionate responses from a world leader, but The Simpsons is no ordinary cartoon. The show is notorious for making a mockery of all that is sacred. No one and nothing is off limits to the family, including Fox, the network that pays the show's bills — and even 20/20's Barbara Walters, who's been parodied along with her View co-hosts.

Though criticism has followed the show's outrageous irreverence — allegations from corrupting America's youth to even causing the decline of Western civilization — the show is a hit. Time magazine called it the best TV show of the 20th century. Loyal fans have a seemingly unquenchable thirst for anything Simpsonian, annually spending millions on collectibles.

The show has its own star on the Hollywood Walk of Fame, and has even been responsible for additions to the English language like Homer's "D'oh!" (Last year, the Oxford English Dictionary added Homer's favorite exclamation, defining it as "expressing frustration at the realization that things have turned out badly or not as planned, or that one has just said or done something foolish.")