The customers are playing right along, merrily puffing away — and sometimes speaking in funny accents and doing a little improvisation, too.

The state Health Department is threatening to bring the curtain down on these sham productions. But for now, it's on with the show.

At The Rock, a hard-rock and heavy-metal bar in suburban St. Paul, the "actors" during "theater night" do little more than sit around, drink, smoke and listen to the earsplitting music.

"They're playing themselves before Oct. 1. You know, before there was a smoking ban," owner Brian Bauman explained. Shaping the words in the air with his hands, like a producer envisioning the marquee, he said: "We call the production, `Before the Ban!'"

The smoking ban, passed by the Legislature last year, allows actors to light up in character during theatrical performances as long as patrons are notified in advance.

About 30 bars in Minnesota have been exploiting the loophole by staging the faux theater productions and pronouncing cigarettes props, according to an anti-smoking group.

"It's too bad they didn't put as much effort into protecting their employees from smoking," grumbled Jeanne Weigum, executive director of the Association for Nonsmokers.

The Health Department this week vowed to begin cracking down on theater nights with fines of as much as $10,000.

"The law was enacted to protect Minnesotans from the serious health effects of secondhand smoke," Minnesota Health Commissioner Sanne Magnan said. "It is time for the curtain to fall on these theatrics."

At The Rock earlier this week, a black stage curtain covered part of the entrance, and a sign next to it with an arrow read, "Stage Entrance." Along the opposite wall, below a sign saying "Props Dept.," was a stack of the only props needed: black ashtrays.

At the door was a printed playbill for that night's program, with a list of names of the people portraying bartenders and security guards. Playing the owner: "Brian."

Courtney Conk paid $1 for a button that said "Act Now" and pinned it to her shirt. That made her an actor for the night, entitling her to smoke. She turned in an understated, minimalist performance, sitting with cigarette in hand and talking to a bass player with the band.

"I thought it was funny that they found a loophole," Conk said. "I'm more of an activist-actor tonight, you could say. I think it's kind of this way of saying what we think about the ban."

While The Rock asks nothing of its actors by way of creativity, a few other bars have been a little more theatrical.

At Barnacles Resort and Campground along Lake Mille Lacs, a "traveling tobacco troupe" dressed in medieval costume on the first theater night. Mark Benjamin, a lawyer who pushed bars to exploit the loophole, wore tights, a feathered cap and black boots.

"Hey, I'm a child of the '60s. I can do a little improv," he said. His improv amounted to speaking in medieval character to other patrons.

In Hill City, Mike's Uptown owner Lisa Anderson has been offering theater night once a week. The bar had a Mardi Gras theme last Saturday, attracting about 30 patrons, most of them in costume.

"I was dressed in a Victorian dress with the old fluffy thing that weighs 500 pounds," she said. "We had some fairies and some pirates and a group of girls — I'm not sure what they were, but they had big boas and flashy makeup."

Though there were no skits, Anderson said some people "start talking with different accents." She added: "It's turned into the funnest thing I can imagine."

One bar on northern Minnesota's Iron Range, the Queen City Sports Place, calls its nightly smokefest "The Tobacco Monologues."

Proving anew there's no business like show business, Anderson said her theater-night receipts have averaged $2,000 — up from $500 right after the ban kicked in. Similarly, Bauman said revenue at The Rock dropped off 30 percent after the ban took effect, then shot back up to normal once the bar began allowing smoking again.

He and other bar owners said they plan to continue putting on theater nights.

"There's no question we were struggling," he said. "And we are extremely nervous that this is going to go away, and we will be back to the way it was."