The lines outside the convention center went on and on, like a slow-motion perp walk of aliens gone AWOL: the robed, pimply Jedis standing next to the ankle-biter in the Batman cape, who followed the three middle-aged dad-dudes dressed as old-school Klingons, not too far from the wand-waving Harry Potters and the tattooed vixens in Vampirella goth gear, complete with bustier and fangs. Then there was the teen-girl with the black frame glasses, her dyed red hair up in barrettes, who wore a T-shirt that read: I {heart} NERDS.

Oh, yeah, big time. Comic-Con International is perhaps the largest gathering of nerds on the planet; nearly 100,000 of them attended the four-day fest that ended Sunday, and nobody loves them more than Hollywood, which has transformed the annual convention into a Cannes for Geeks, a Sundance for the fanboys (and girls) who can drive the success of the genre films of sci-fi, fantasy and horror, which are essentially the only movies making blockbuster money these days (think: "War of the Worlds," "Fantastic Four," "Batman Begins" and "Charlie and the Chocolate Factory").

When Comic-Con began 36 years ago, it was a few hundred people trading Golden Age issues of Flash and Green Lantern. Now, the actual comic books have been shoved to the perimeter of the cavernous downtown convention center, and movies and video games made about comic-book characters have taken over.

And if Comic-Con represents the nuclear reactor that generates early buzz for a film, the white-hot uranium core here has got to be Hall H, where hour after hour, attendees fought for one of the 6,500 seats to watch teasers and trailers and outtakes from upcoming attractions (many shown for the first time), and to hear the movie directors and actors on the panels promise the fans that they will deliver the goods. (Or else face the wrath of the nerd wronged.) Most of these films will not open for months, and some not until 2007.

This year, the talent making the trip to San Diego included Adrien Brody, Natalie Portman, Karl Urban, Kate Beckinsale, Jack Black, Charlize Theron, Naomi Watts and the Rock. Universal showed coming attractions for "Doom," the R-rated splatterflick based on the video game. The Rock pledged to Hall H that "the movie kicks [butt]." Then they showed the trailer. Audience reaction: good, not great. Then they showed a still-rough clip featuring Urban, filmed from his "Doom" character's point of view, in the "First-Person Shooter" mode of the video game, and the crowd went nuts as he blew the heads off of chain saw-wielding demons.

Disney gave a taste of "The Chronicles of Narnia: The Lion, the Witch and the Wardrobe," which won't be out until Christmas, and everyone watched to see how different it would look compared with the "Lord of the Rings" trilogy (since the New Zealand designers who did J.R.R. Tolkien are now tackling C.S. Lewis). Narnia looked plenty different, and the applause was enthusiastic, with some attendees on their feet.

And on it went: Warner Bros. featured a glimpse of "Superman Returns" and "Harry Potter and the Goblet of Fire." Sony showed off "Ghost Rider." And Peter Jackson sent in a raw clip from his "King Kong," still in the works, that showed the big monkey taking a bite out of a T. rex, as if the dinosaur was a BK Broiler. (And so, early word in the Web chat rooms on Sunday? "Kong" could rock.)

"It's total geek central," explains Garth Franklin, founder and editor of the movie site, bloodshot and google-eyed, who basically lived in Hall H for four days. He says a movie's success can be made or destroyed by its reception at Comic-Con, where the fans are not only intimately knowledgeable about the source material (the game, the comic, the book; they know their Narnia), but are also fiercely protective of their superheroes and wizards. And because of the Internet, their opinions count. "They take all this very seriously," says Franklin, one of better known of the hundreds of online journalists covering the Con. "And they post," he says. (Hundreds of pictures taken with digital cameras at the convention are already wending their way around cyberspace.).

In a fierce marketplace for genre, sites like Darkhorizons and Ain't It Cool News and are king. Forget the New Yorker. Here, a teenager with strong opinions and text-messaging becomes Pauline-Kael-with-typos. Call it word of mouth or buzz or viral marketing, the studios now realize they must inoculate this fan population early and often if they hope to open big at the box office -- or go the way of "Catwoman," a certified flop and loathed by the Comic-Con community, which saw the movie as a crass exploitation of a beloved character. Plus, they didn't think Halle Berry was right for the role.

So into the maelstrom of the convention center on Saturday afternoon came director Rob Zombie and Lions Gate Films to launch "The Devil's Rejects," Zombie's super-violent road-rampager about a scary clown and his family of mass-murdering psychopaths. Here, they hope to find their audience.

"Because the people here are the real fans, the extreme fans," Zombie explains before he enters the hall, taking a few moments to sit with a reporter at the Omni Hotel next door. "Everybody is a fan of something, I know, but these people build their lives around it. It's a lifestyle. They talk about movies two years before they come out. If they hate something? Man, it's a hard hurdle to get over. And every genre movie lives or dies by the hardcore fans."

You might not have heard of Mr. Zombie (real name: Robert Cummings), lean and tousle-haired and etched in tattoos, but obviously enough members of the Comic-Con community know his work that he requires a pair of extra-large bodyguards, so as not to be mauled when he signs autographs. Zombie is both artist and entrepreneur -- he is the lead singer in the hardcore rock/punk hybrid band White Zombie, the director of dozens of musical videos, the creator of a comic book serial and the auteur behind the cult film "House of 1000 Corpses," which introduced the Firefly family, who make their return to the screen in "The Devil's Rejects."

Zombie says he has been intimately involved in the marketing of this project, in part because he believes his fans can smell a poseur a mile away. "You know the studios hire companies to put up posts on the Internet pushing a film? Well, the fans can spot these, and you'll see them post back, 'Get off the site you studio shill!' You have to be real or they'll just laugh at your trailer. I'm not kidding."

Zombie says he believes it was only in the last few years that Hollywood began to really understand the importance of this audience. "Before, it was, like: Look! There's a bunch of kooks dressed in stormtrooper outfits. They laughed at them. But nobody thinks it's funny anymore." Zombie thinks this is kind of a revenge of the nerds: "Everything you were tortured for liking as a kid is now a $100 million blockbuster."

To market the "Rejects" project, Lions Gate set up an elaborate stage to the convention floor, which endlessly rotated the movie's many trailers. It also brought the Cadillac used in the movie (rusty with fake blood) and a bunch of makeup artists, who spent every day painting clown faces on attendees to make them look like the deranged father figure Captain Spaulding (actor Sid Haig). They painted hundreds of people, who then wandered around the Con as walking billboards.

John Hegeman, head of international marketing for Lions Gate, is on hand, a studio suit dressed down in shorts and a "Devil's Rejects" T-shirt. Hegeman seems genuinely excited by the convention. "Look at the people." He is pointing. "Moms. Pushing strollers. Dads. College kids. Black. Asian." Oh, and someone dressed as Gen. Grievous from "Star Wars: Episode III -- Revenge of the Sith." Says Hegeman: "This isn't a demographic. It's a psychographic profile. Age has nothing to do with it. Gender has nothing to do with it. They're fans."

To hear Hegeman describe it, fans are pure and real and sort of sweet in their innocence. But you better not disappoint them, lest you get a little taste of the flame on. These people -- mostly adults, by the way -- are some of the friendliest conventioneers this side of a Omaha Shriners' gathering. Very mellow, very polite. Just don't them started on how the Incredible Hulk was done wrong by Ang Lee.

Hegeman says his studio and others not only sell their films at Comic-Con, but make the rounds at a dozen other genre conventions around the country -- at events sponsored, for example, by Wizard Entertainment or the Fangoria magazine Web site, plus Wonder-Con in San Francisco and Mega-Con in Orlando. "It's like a band on constant tour," he says.

Meanwhile, the studios are also "feeding assets" to the fan and genre movie Web sites, meaning they provide a constant stream of short teasers from the upcoming movies (Lions Gate doled out 45 clips for "Rejects" over the last nine months), as well as providing backstage looks and interview opportunities with stars and designers and directors.

So there's no longer such a thing as peaking too early? Hegeman shakes his head. "Not with the core." Then he amends: "As long as you have the goods." At their booth, Zombie is doing an on-camera interview with the tabloid TV show "Access Hollywood," which Hegeman describes this way: "Fine, sure, but it's not our audience."

Their audience shows at the premiere of the movie, held Saturday night, complete with a red carpet. The theater is filled with Comic-Con attendees whose faces were still painted in clown makeup, though by now a bit runny, like Tammy Faye after a good cry. The lights go down. The guts fly. Innocents are slaughtered. Macabre jokes leaven the violence. And voila, the cast and crew get a standing ovation.

Outside in the lobby, Andy Gould, Zombie's manager and a producer on the film, is asking fans what they thought, and happy to hear the first, early take. Then he wiggles his fingers like a typist and says to a reporter, "We'll go online later and learn what they really think -- but so far, so good." True enough. On the street corner, fan Felix Trevino, 22, a community college student, is still in makeup. His instant-pundit take? "I loved the look, that '70s look, like 'Chainsaw' " -- as in "The Texas Chainsaw Massacre" -- "and I laughed. It was funny. Especially Captain Spaulding." He then describes several scenes at great length.

Any disappointments? "I thought it would be more violent," Trevino says, shrugs, like maybe next time. His recommendation? "I'd tell anyone to see it. It's sick."

Even killer clowns gotta eat: Mike Miller, left, and Conrrado Lemus, dressed as "The Devil's Rejects" character Captain Spaulding, grab a snack.Nerds -- that is, conventioneers -- wonder through the exhibts at the Comic-Con 2005 in San Diego.Rob Zombie promoted his bloodfest "The Devil's Rejects" at Comic-Con.