LOS ANGELES -- As Bart Simpson skips into his 18th season of TV mischief, fans will be glad to know that creator Matt Groening sees no end in sight for the wayward lad or "The Simpsons."

Groening's reasoning is sound: The show, which returns tonight, is fun to make, fun to watch, just earned its 23rd Emmy and is finally jumping to the big screen with a summer 2007 movie about Bart and the rest of Springfield's first family.

"My attitude at this point is, as long as the people who work on the show are having a good time, let's keep doing it," he said. "We've always tried to entertain ourselves and figured that the outside world would be entertained if we were making ourselves laugh."

The key is to keep surprising the audience, which he acknowledged has become tougher because the show has "covered a lot of territory" through the years. It has, in fact, brilliantly lampooned nearly every aspect of American life and culture.

"But there's a really good-natured spirit of competitiveness among the youngest writers on the staff who basically grew up watching the show and have a great memory for everything that's gone before," he said.

They also don't want to be the ones who disappoint the nation, not to mention the world. The series is seen in more than 70 countries, which along with scads of "Simpsons"-based merchandise has made it a reported billion-dollar cartoon cash cow for Fox parent News Corp.

"The people currently on staff are determined not to be the staff that caused the show to crash and burn. But also to try to top ourselves," Groening said.

"The Simpsons" has been renewed by Fox through its 19th year. The ensemble voice cast includes Nancy Cartwright as Bart, Dan Castellaneta as dad Homer, Julie Kavner as mom Marge, Yeardley Smith as sister Lisa, Harry Shearer as boss man Mr. Burns and Hank Azaria as police Chief Wiggum (Azaria and several others in the cast perform multiple voices).

Last month, it won its ninth Emmy for best animated series and has received best voiceover performance and other honors. Groening called the latest award "a shot in the arm. ... I thought people might be jaded but, no, they weren't."

The program is known for its stellar guest stars and promises not to disappoint this season. In an episode in which Lisa helps Moe the bartender become a poet, she encounters Gore Vidal and Tom Wolfe, voiced by the literary giants themselves.