Sundance and Toronto relegate their genre pics to midnight slots, but at Fantastic Fest in Austin, Texas, audience-friendly sci-fi and horror offerings are the main attraction, with world premieres of such prestige titles as “There Will Be Blood” and “Apocalypto” mixed in for good measure.

“We’re not just about the blood and guts. What we’re trying to do is expand the definition of ‘genre.’ A film like ‘No Country for Old Men’ is a genre film,” says Fantastic Fest co-founder (and Ain’t It Cool News honcho) Harry Knowles, who lends his studio and filmmaker connections to securing the fest’s “secret screenings.”

(Mel Gibson called him two days before the 2006 fest from Oklahoma, where the helmer was screening “Apocalypto” for a select Native American aud, to propose debuting a work-in-progress print in Austin.) “If you look at Daniel Day-Lewis’ character in ‘There Will Be Blood,’ was there truly a better psychopath that year?”

Suffice it to say, Lars von Trier’s “Antichrist” will get a very different reception in Austin than it did in Cannes. While economic times are forcing most sprocket operas to scale back, the organizers of Fantastic Fest expect this year’s installment (Sept. 24-Oct. 1) to be their biggest yet, with overall attendance swelling by as much as 20%.

To accommodate the fest’s fanboy badgeholders, four of the galas, including Fox Searchlight comedy “Gentlemen Broncos” (about a wannabe fantasy scribe) and U release “Cirque du Freak: The Vampire’s Assistant” will screen in Austin’s historic 1,300-seat Paramount Theater.

But growth is a mixed blessing, according to lead programmer Tim League, who runs the Alamo Drafthouse venue where the rest of the screenings take place under a single roof.

“What we like about the festival is that there’s an intimate feel,” he says.

Attendees are encouraged to mingle with the filmmakers after screenings, getting drunk and singing karaoke at high-concept parties (such as the “Donkey Punch”-themed boat bash on Lake Travis or the “City of Ember” after-party hosted at a giant cave outside town).

Press-shy talent find the event attractive, since it allows them to screen their films for receptive auds while dodging mainstream critics and the usual red-carpet throng — one of the reasons “There Will Be Blood” director Paul Thomas Anderson agreed to unveil the film there in 2007.

Such high-profile premieres have helped put Fantastic Fest on the map, but it’s the discovery of foreign and first-time genre helmers that most excites League and his cohorts. Their tastes may be outre (a film called “Human Centipede” features a particularly gruesome variation on the Frankenstein myth, for example), but the programmers scour the globe looking for treasures such as Swedish arthouse hit “Let the Right One In.” This year’s lineup includes entries from 26 countries, from Estonia to Indonesia.

Though popular with Euro cinephiles, genre fests haven’t taken off as much in the U.S. It was at the Sitges’ 2002 sprocket opera that League and Knowles wondered why there was no like-minded showcase back home. Now in its fifth year, Fantastic Fest has already become the country’s largest genre fest, second only to Montreal’s Fantasia in all of North America.

Fantastic Fest’s appeal to the Comic-Con crowd goes without saying, but the event’s credibility lies in its growing status among industryites. Magnolia’s Tom Quinn was the first distributor to bite, picking up three pics in 2007: Nacho Vigalondo’s “Timecrimes” and Chilean action movies “Kiltro” and “Mirageman” from director Ernesto Diaz Espinoza. (After world premiering in Austin, “Timecrimes” went on to play Sundance, where UA bought remake rights.)

“Once we came out of there with three movies, everybody woke up,” claims Quinn, who acquired “Chocolate” by director Prachya Pinkaew (“Ong-bak”) at Fantastic Fest the following year. “Even though I’d seen it prior on DVD, I did not decide to buy ‘Chocolate’ until I went to see it with an audience in Austin.”

So, while Knowles and League aren’t opposed to the stories of Mongolian goatherds or navel-gazing mumblecore movies that fill the programs of other festivals, they just don’t have any space for such pics at Fantastic Fest.

“It’s like a film festival with the boring parts cut out,” Knowles says.