SCHENECTADY — Proctors may be better known for its Broadway shows and its elaborate ballets, but this weekend, it will host a marathon of space explosions, fantastical monsters and even an anti-gravity striptease.

The city’s first science-fiction film festival, “It Came From Schenectady!” will run for 24 hours straight this weekend, beginning Saturday at noon. Already, more than 300 of the 400 seats in the GE Theater have been sold, surprising even the organizers of the event.

“All of us are big sci-fi fans and all of us are tasked with finding events for that room,” said Proctors advertising manager Peter Hughes. “We were tasked with drawing in groups that aren’t the Proctors audience already — people who may not want to see ‘Momma Mia!’ And we said, ‘Well, we’d really like to see a sci-fi film festival.’ But I was wondering how many people would come.”

He was so reassured by the sales that he’s now hoping to expand, possibly offering a horror movies marathon as well as sci-fi next year.

Hughes and his fellow event organizers have named themselves “the dorks in tin foil hats” and plan to stick it out for all 24 hours of the marathon. Although the festival featured classic movies, they’ve added an element from one of the blockbusters of this summer: “Iron Man” has become a verb, meaning “to stay awake for an entire sci-fi film festival.”

“At least 40 people have guaranteed they’re going to Iron Man the whole thing. I’m going to Iron Man it too,” Hughes said.

Once the sci-fi fanatics got permission to plan their festival, they gleefully hit upon “It Came From Schenectady!” as the perfect name. The phrase is the title of a book of short stories by Barry Longyear.

It was only after everyone agreed on the name that it occurred to them to check with Longyear. To their delight, he not only granted permission but said he wanted to attend.

Longyear will answer questions for an hour beginning at 8:44 p.m. Saturday. A movie made from his book, “Enemy Mine,” will also be aired at 2:07 p.m. Saturday.

a true alien

Despite naming one of his books after Schenectady, Longyear isn’t from the area. He lives in Maine and got the title for his book from Harlan Ellison, a well-known sci-fi author who wrote some of the most famous “Star Trek” scripts.

Ellison is also known for his sharp sense of humor, and after he had been repeatedly asked where he got all his ideas, he once said he paid for a service in Schenectady to send him fresh ideas regularly. The phrase caught on and many sci-fi authors now offer the same answer when asked about the genesis of their ideas.

After Longyear’s talk, the festival will screen a documentary about Ellison, “Dreams with Sharp Teeth,” at 9:40 p.m. The festival will also include one of Ellison’s movies, “A Boy and his Dog,” at 4:15 p.m.

On Sunday, Edie Meyers will answer questions at 9:21 a.m. Meyers produced the television series “Star Crash.”

Between movies, viewers may find prizes tossed onto their lap — “We have T-shirts to throw at people,” Hughes said — and can win DVDs and ray guns by correctly differentiating between “Dr. Who” and “Star Trek” aphorisms, among other games.

“Quick!” Hughes said. “Hand of Fear! Which is it, ‘Dr. Who’ or ‘Star Trek,’ or did I just make that up?”

(To those who haven’t seen all 10 incarnations of “Dr. Who,” the Hand of Fear possessed one of its characters in 1976.)

The games aren’t the only reason to watch the movies on the big screen. Hughes believes it’s far more fun to watch movies in a group.

“Sure, you can see anything you want now at home, with Netflix and YouTube and Blockbuster,” he said. “So what’s the point of going to a big room? Because it’s fun. And if you’re going to do it, why not do it for an insane amount of time?”

Muddy Cup and the Proctors snack counter will remain open for the 24-hour festival, but viewers are also allowed to bring in their own food. Couches will be set up on the first two rows, and viewers are encouraged to treat the theater as their living room, bringing in sleeping bags and pillows.

Most of the shows can be seen by a PG audience, with the exception of the R-rated “Tokyo Gore Police” (which airs at 2:10 a.m.). “A Boy and his Dog” involves “adult” themes — in the post-apocalyptic Earth, a girl from a sterile community seduces a boy in hopes of being impregnated.

As for that anti-gravity striptease, there’s no full nudity — the woman’s body is blocked by the opening credits of “Barbarella.”