This Saturday at 8 p.m. an audience will gather at Rose Wagner Theatre for an evening of five short plays.

But the directors have yet to read the script.

The actors have yet to memorize their lines.

And the cast has yet to rehearse.

That's because the plays have yet to be written.

This is SLAM, Plan-B Theatre Company's annual "Day O' Crazy," where the company spends 23 hours writing, memorizing, rehearsing and hour 24 is spent performing.

"Every year when it's over I say I'm never, ever going to that again, ever," says Kirt Bateman, who has been involved in four of the five SLAMs both as an actor and director. "And then you look back on it and you just realize what an incredible day. It's almost like parachuting — you've just gone through this incredible rush of a day and you don't want to miss out."

SLAM, which has been lighting a fire in the bellies of local theater folk, is celebrating its fifth birthday.

"We had no idea that this would be anything other than a hoot one year," said Jerry Rapier, producing director of Plan-B, "It is truly inspiration that you're seeing on stage."

If you're new to SLAM or want a peek behind the scenes, here's how it works:

Friday at 8 p.m., the playwrights arrive at the theater. Prior to that, Rapier and his staff have created the soon-to-be-written play titles.

Then they assign the cast. "One year we did it by descending shoe size. We've put folders upside down so nobody could see and we said go and pick. Last year we just laid them out and they ran and grabbed people."

With the title of their play, the cast and an idea of basic available props, the playwrights are sent home — time to write.

"I live in Provo. So from downtown Salt Lake City to my house it's 45-50 minutes, and that's great," said Eric Samuelsen, five-time SLAM playwright and a professor of playwriting at Brigham Young University.

"My first thought was 'crud ... I've got basically two hours less time than everybody else.' But what I've found is that an hour drive back is just fantastic. I basically get the play kind of mapped out in my head."

"At 9 a.m. the plays are due," Rapier explains. "Sometimes the paper is still warm because it's just been printed."

The playwrights can head home at this point. "I go home and I try to nap, which is impossible," Samuelsen said. "The whole day I just imagine what did they do with it? Do they get it? Did they get the jokes?"

Time to rehearse.

"As a director, you read it for the first time when the actors read it out loud," Bateman said.