They’re yellow, they’re dysfunctional, and they only have four fingers on each hand.

But “The Simpsons” are posed to become television’s all-time longest running situation comedy.

Now in their 14th season of animated social satire, the doughnut-scarfing, kid-strangling family man, Homer Simpson, and all the crazy citizens of Springfield show no signs of aging.

The show’s producers have already signed a contract to go another two seasons with the nuclear family of five. Sunday will be the celebration of its 300th episode, airing at 8 p.m. on Fox.

The new contract will put a total of 16 seasons under the beer-gut belt of Homer J. and the gang, giving them the title of longest-running sitcom in the history of television. The current record of 14 seasons is held by “The Adventures of Ozzie and Harriet.”

Representatives at central Iowa’s Fox network affiliate, KDSM Fox 17, say “The Simpsons” is one of the highest-rated programs on the channel’s lineup. Nicole McPherren, KDSM Fox 17 promotions manager, says the station is proud of the show’s longevity.

“We are really excited,” McPherren says. “Having a comedy you can rely on every week to be just as funny today as it was five years ago is just amazing.”

In celebration of the 300th episode and America’s favorite animated family, Fox will air three back-to-back episodes Sunday, starting at 7:30 p.m. with “How I Spent My Strummer Vacation,” the landmark 300th episode “Barting Over” at 8 p.m., and “I’m Spelling As Fast As I Can,” at 8:30 p.m.

Guest stars have always been a highlight of “The Simpsons,” and the 300th episode is no exception. Lenny Kravitz, Elvis Costello, Tom Petty, Brian Setzer, Jane Kaczmarek, Blink-182, Tony Hawk and George Plimpton will make appearances during Sunday’s three episodes.

“The Simpsons is such a great show and the network and other affiliates are doing a lot of promotions for the mark of the 300th episode,” McPherren says.

Promotions include various local radio stations giving away skateboards, T-shirts and a year’s worth of doughnuts to fans that can best imitate their favorite Simpsons character, she says.

A history of humor

“The Simpsons,” created by Matt Groening, started out as a cartoon feature on “The Tracy Ullman Show” in 1987 as a series of 30-second shorts. These shorts included the full family of Homer, Marge, Bart, Lisa and Maggie.

The Simpson clan made their first half-hour comedy premiere on Fox on Dec. 17, 1989. Over the years, the characters’ appearances have changed, the limelight has shifted from Bart to Homer, and the comedy has gone from knee-slapping comedy to more adult humor.

“There were many reasons the show was successful, one of which was we were in the right place at the right time,” Groening said this week in an interview with the Associated Press. “I don’t think ‘The Simpsons’ could be on any other network, even today.”

Although all “Simpsons” characters have their own respective personalities, backgrounds and tag lines, many share one common ground — their voice. Each of the 44 characters in the beloved town of Springfield are vocalized by just six actors.

The actors and artists are Hank Azaria, Nancy Cartwright, Dan Castellaneta, Julie Kavner, Harry Shearer and Yeardley Smith. Six different people — 44 different characters.

Groening says the fact this comedy usually pulls its humor from sharp-edge social commentary, authority figures and institutions such as public education, politics, the entertainment industry and law enforcement.

Take former President George H.W. Bush and first lady Barbara Bush, for example.

In September 1990, Barbara Bush said in an interview with People Magazine that “The Simpsons” was”the dumbest thing I have ever seen.”

Two years later at the Republican National Convention, then-President Bush decreed that the nation ought to be “more like the Waltons and a lot less like the Simpsons.”

Cartoons don’t get mad, but their creators get even.

The “Simpsons” writers responded in 1996 with “Two Bad Neighbors,” an episode in which the Bush family moves into a house across the street from the Simpson family. Bart, Homer and the president get off on the wrong foot. The feud comes to a head when the former president and his chubby neighbor get into a fist fight. Eventually, the Bushes realize they don’t belong and leave Springfield entirely.

“Periodically we get in trouble,” Groening says. “We offend somebody and Fox feels intimidated by them.”

Fox isn’t complaining too loudly, however.

The show is widely syndicated, is seen in several overseas markets and is averaging 14.3 million viewers this season alone, according to Nielsen Media Research.

Selling “The Simpsons”

With viewership comes merchandise, and “The Simpsons” is no slouch. There is a multi-million dollar market of “Simpsons” products. Jeanette Foshee, secretary for ISU Extension communication services and long-time “Simpsons” fan, has contributed more than her share to the franchise’s marketing success.

“I have just about every figurine made by [toymaker] Playmate of the characters,” she says. “I have Homer in a radiation suit that glows in the dark…a Bart cookie jar, key rings, bath soaps, posters, DVDs, CDs and a couple of book bags — one in which you unzip Homer’s belly.”

Foshee has collected her “Simpsons” memorabilia from around the world — from Ames to Australia.

“I have my unusual, hard to find things of all characters,” Foshee says. “But my favorite is Bart, by far.”

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