The new TBS comedy series 10 Items or Less promises to be something other than your typical TV sitcom.

For one thing, the 30-minute show, which premieres Monday, will be on at 11 p.m., a time when most people are accustomed to watching their local news or dusty old sitcom reruns, if they have the television on at all.

But what really sets the show apart from more traditional TV fare is that it will be almost entirely improvisational. The actors won't work from scripts, they won't rehearse, and they won't know from one day to the next what they'll be saying or doing on camera.

The show's creators - John Lehr, Nancy Hower, and Robert Hickey - write scripts for the series, but they contain no dialogue, according to Lehr, who also stars in the program.

"Robert, Nancy, and I write detailed outlines for each show, but we don't show the script to the actors," Lehr explained in an interview. "The actors learn what the episode is as they are acting it. All of the dialogue in the show is completely improvised. The actors get the situations and scenes, but no lines."

Lehr is a veteran comedic writer and improv performer who once worked at Chicago's famous Second City. In 2003, he produced and starred in Memron, an entirely improvised spoof documentary based on the Enron scandal. Both Hower and Hickey, a University of Michigan graduate, also were involved in the feature-length movie, which was popular at several film festivals around the country.

10 Items centers on a small, family-owned grocery store outside Dayton called Greens & Grains. When the store's owner dies, his inept son, Leslie (played by Lehr), returns home from New York to try to keep the business going. The store is staffed by a dysfunctional bunch of goofballs who fully expect their bumbling new boss to run the store into the ground.

The employees include Carl (Robert Clendenin), a demented, middle-aged stock clerk; Richard (Christopher Liam Moore), a prissy cashier who wants to be a professional ice dancer; Yolanda (Roberta Valderrama), an outspoken Hispanic produce worker; Ingrid (Kirsten Gronfield), a quirky customer service rep who thinks her life is a renaissance festival, and Todd (Chris Payne Gilbert), a testosterone-fueled butcher who plans to be a stock car driver.

Leslie tries to rally the troops to keep the store afloat, slapping together an employee handbook with inspirational slogans he's ripped off from unlikely places. A favorite: "The needs of the many outweigh the needs of the few." Source: Spock in Star Trek II: The Wrath of Khan.

Down the street from Greens & Grains is the giant Super Value Mart, managed by Leslie's old high school crush, Amy. She ignored Leslie in school because she was a beauty queen and he was a nerd, and now she wants to drive him out of business so she can demolish his store and expand her parking lot.

Improvisation isn't new on television; HBO's Curb Your Enthusiasm, NBC's The Office, and ABC's Sons & Daughters are among the shows that have employed the approach with some success. But 10 Items or Less uses "long-form improv," which calls for a continuing series of improvised scenes that include an evolving plot and character development.

You'd think the lack of written dialogue would make things easier for the program's writers, but that's not the case.

"Oddly, because the show is improvised, the three of us have to write a lot more," Lehr said. "If an actor takes the show in a new direction, we have to be flexible and adjust the show accordingly."

In addition to the series' actors, many scenes also feature additional, unexpected cast members. That's because the show is videotaped during regular business hours in a real grocery store in Reseda, Calif.

"The store is open for business, so actual customers are shopping around us as we shoot," Lehr said. "No one seems to care. We're all dressed in uniform, so people are asking us where certain products are shelved all the time.

"If a customer walks into the shot while we're in the middle of a scene, I'll speak to them, and often this stuff will get into the show."

10 Items or Less is the first series created for TBS's new late-night block of original programming. Other shows include My Boys, a sitcom about a female sportswriter, which debuts Tuesday night; a puppet talk show from the Henson Co., creator of the Muppets, and a possible sketch comedy series.

Lehr said he feels a certain amount of pressure to succeed, but he's still able to keep things in perspective. "I keep reminding myself that we are making a TV show here," he said. "We're not curing cancer, and we're not putting a man on the moon. We're just trying to crack some people up."

The degree to which the ensemble cast succeeds will help determine whether a new late-night viewing tradition is being created, or whether 10 Items will wind up in the express checkout line.

First Published November 23, 2006, 11:03 a.m.