CODE NAME: YELLOW HARVEST. It's a perilous project that's required years of plotting (up to 18, depending on who's counting) and the complicated synergies of hundreds of individuals (some not quite human). It has triggered surprise, curiosity, glee, anxiety, and a nationwide epidemic of finger-crossing. But on this June afternoon in L.A., it's just a bunch of guys trying to beat a deadline.

Tucked away on the Fox lot, inside a nondescript trailer labeled Stacked Productions — the placard from Pamela Anderson's 2005 sitcom was left hanging to foil interlopers — two dozen staffers slave over monitors containing America's most famous animated family in various high jinks, like Homer spotting a fallen treat: ''Ooooh! Floor popcorn!'' Signs of time crunch are everywhere. A chart of scenes with titles like ''Eski-Moe's Tavern'' is covered with colored stickers indicating completion status. A calendar is smothered in notes about production sessions and deadlines. And then there's the world's least gentle reminder: Above one poor soul's workstation, a digital clock counts down the time left until this motion picture of major proportions, The Simpsons Movie, must be surrendered to the studio authorities. ''We use it as a means to frighten ourselves,'' explains producer Richard Sakai, studying its unforgiving flashes: 16 days, 9 hours, 42 minutes, 6 seconds...5 seconds...4 seconds...

A doughnut's throw away, the film's writer-producers — James L. Brooks, Matt Groening, Al Jean, and Mike Scully — give notes on newly minted footage. ''If a joke's not working,'' deadpans Scully, ''put a loud car horn over it or a plane flying by.'' In one scene, three townsfolk come pleading to Mr. Burns. ''So you want some of my electricity, do you?'' snickers the sinister senior tycoon. ''Well, for once, the rich white man is in control!'' When the Springfield residents are chased away by ferocious hounds, the scribes look relieved. ''That's an area we've changed 300 times,'' says Jean, shaking his head. ''We should put in all the takes,'' cracks Groening. Retorts Jean: ''It'd be longer than Gone With the Wind.''

Indeed, this has already become one epic cinematic journey. ''It's very hard to believe the end of the road is here,'' muses Brooks. ''You're crazy not to be excited, and you're crazy not to, um, uh...'' He trails off before finding the right words with a grin: ''...wake up on a mattress full of flop sweat.''

No need for nerves, guys: You're only making one of the most anticipated films since the concept of ever was invented. On July 27, Fox's worshipped, Emmy-encrusted comedy — featuring Homer Simpson, a man so dumb he once called a spoon ''that... metal deelie...you use to...dig...food'' — finally hits theaters. The Simpsons Movie promises to be an emotional saga about a man who falls for a pig, ignores his wife's advice, and potentially dooms his town. It also aims to honor the show's rich history (coming this fall: season 19) with physical gags, corner-of-your-screen winks, and beloved Springfieldians (Nelson! Chief Wiggum! That old man with the ZZ Top beard!). Yet this 35mm mission wasn't easy: Cows were had, shorts eaten. But after all the blood, sweat, and Duff beers, Homer's helpers think they've created something entertaining enough to pay for, maybe even woo-hoo!-worthy. And they know what's at stake: a billion-plus-dollar franchise's good name. ''Nobody wants to be the one that rams the ship into the iceberg,'' says Groening, who first scribbled the Simpson clan in 1987 for Brooks' The Tracey Ullman Show.

Or as Jean sums up: ''As an event, I think it'll be somewhere between Sgt. Pepper's the album and Sgt. Pepper's the movie.''

NEXT PAGE: ''It was an odd contract dispute — we were arguing against a green light.''