"Ladies and gentlemen, you have one minute to put your superhero names in the severed Spider-Man head bucket."

So began last Saturday's performance of "Ka-Baam!!," the superhero improv show at Huge Theater. Audience members were asked to scribble made-up superhero names onto scraps of paper and put them in the Spidey Halloween bucket onstage. The three winning names would be portrayed by a group of actors, improvising their lines over the course of two hours.

For people who enjoy their performance art polished, this whole scenario probably sounds like a disaster in the making. But if you like a little edge in your entertainment, Huge would like your business.

Huge Theater opened quietly in December near the corner of Lake and Lyndale in Minneapolis. Its founders call it the only dedicated stage for long-form improvisational comedy in the Twin Cities. They'll celebrate with a true grand opening party on Friday.

Improv is often treated as "an ugly stepchild" in the Twin Cities theater scene, said Huge co-founder Jill Bernard. The easiest way to describe long-form improv is probably to say what it's not. It's not stand-up comedy, although that's the most common assumption. And it's not short-form improv, where games and a greater amount of audience participation dictate the stage antics (you can see that at Comedy Sportz in Uptown).

For the most part it's unscripted theater. In the case of "Ka-Baam!!" the actors are creating a brand-new superhero comedy right before your eyes. The cantankery on Saturday began with these three would-be heroes: Banana Boy, the Indomitable Ooze and Captain Jesus. The messiah, in this case, was played by a woman (Hannah Kuhlmann).

Huge started as a five-person troupe in 2005. After producing shows around the Twin Cities and organizing the annual Twin Cities Improv Festival, three of the members thought it was time to go all-in and open their own place. One problem: "The improv community does not have a lot of money," Bernard said. She and co-founders Butch Roy and Nels Lennes spent most of 2010 furiously raising money to open the theater in the former Lava Lounge clothing store.

Huge has an ambitious schedule, booking shows six nights a week. There's something called "The Mustache Rangers" on Thursdays. Bernard performs a solo improvised musical called "Drum Machine" on Saturdays. Then there's "Overheard in Minneapolis," based on the website of the same name, which features awkward conversations overheard in the city. (Woman at Costello's Bar: "You can't even see her cervix in that picture anyway, so who cares?!") But the most popular night at Huge is Sunday's "Improv-A-Go-Go." Think of it as an elaborate open mike for improvisers.

In the second act of "Ka-Baam!!" Kuhlmann and her compatriots were introduced to the night's supervillain: The 50-Foot-Tall 30-Year-Old Hipster. He came from outer space, riding a massive bicycle and demanding Earthlings give him Joy Division tapes (not CDs). As Captain Jesus, Kuhlmann and her fellow actors defeated the giant by wrapping him in Ed Hardy T-shirts (a terrible death for a hipster).

This probably all sounds a lot less hilarious than it actually was. But that's the thing about improv: You have to see it to believe it. As Roy put it: "Yes, I have to cop to that fact that I can't absolutely promise that each show is going to be great. But I can promise that this will be the best version of the performance, because it will never be seen again."

"It hasn't exactly been a cakewalk," Bernard said. "But we make mistakes and we learn from them instantly. We're improvisers: We roll with the punches."