But Bart's voice is coming out of a petite blonde wearing a fluffy, bright-pink wrap. And mom Marge's towering blue hair is brown and tastefully cropped.

The event was a "table read," when the cast of The Simpsons gathered with a roomful of writers, producers and guests, using their imaginations to conjure up the animated family with the distinctive mustard hue.

It was just one of the steps toward crafting an episode of the Fox series that begins its 16th season at 8 p.m. Sunday on Channels 19, 45 with its annual "Treehouse of Horror" special. The run is remarkable for any show - but especially for one like this.

Irreverent, witty and willing to take on anything from politics to religion to family values, The Simpsons has provided a rare bit of spice for the oatmeal-bland bowl of TV broadcasting.

The table read, held in an oversize trailer at the Twentieth Century Fox studio where the series is produced, itself is a symbol of the show's enduring popularity. A decade ago, it finished the season as the 67th most-watched show; it was No. 69 last season with 10.7 million viewers and won its time period among the 18 to 49 age group.

Actors, producers and writers sit at a massive conference table. Invitation-only visitors ring the table. (Noticeably absent are the network executives; The Simpsons has a rare stipulation, won by executive producer James L. Brooks, limiting Fox meddling.)

"It's sort of the hottest ticket on the lot," said Yeardley Smith, who voices young Lisa, the wise Simpson daughter.

"People often come for the fun and bring their children," said Al Jean, an executive producer who's been with the series since it was spun off in December 1989 from Tracey Ullman's Fox series.

It's a treat for observers but serious work for the cast and producers. This is the first time a script has been performed after months of writing and revision.

This particular week it's also the first time the actors have seen the script.

The assembled performers include Smith; Dan Castellaneta, who received his third Emmy this year for voicing Homer and whose other characters include Krusty the clown and Grampa Simpson; Nancy Cartwright as Bart; Julie Kavner as Marge; and Harry Shearer, who does an array of voices, including Ned Flanders and Mr. Burns.

Absent is Hank Azaria, who was in New York rehearsing a new musical. Azaria's characters, including convenience store owner Apu and police Chief Wiggum, are voiced for now by another actor.

They're working on an episode that won't air until next season, typical for a labor-intensive animated series. A roughly 21-minute episode takes about nine months to create, including the animation work done domestically and in South Korea.

In the script at hand (written by Danny Chun), Marge and Bart are engaged in unusual mother-son bonding, breezing through Springfield on a tandem bicycle and singing "Sweet Home Alabama."

Marge: "I can't remember our last outing together."

Bart: "It was to see that court-appointed psychiatrist."

Marge: "Oh yeah. He should never have let you near that letter opener."

The actors move briskly through their lines and most of the jokes draw guffaws from the room. But one shaggy-haired figure proves a tough customer, rarely even smiling - series creator and executive producer Matt Groening.

"He's not an easy laugh, so when you get a laugh out of him you feel like, 'Yes!' It's a big deal," said Smith.

Just how durable is The Simpsons, which has the cast signed through season 19? There will be a 20th season at least, Jean figures, allowing it to match Gunsmoke as the longest-running scripted show in prime-time.