A couple of characters for your consideration

Contemporary American comedy consists of two schools: movies written by Christopher Guest and Eugene Levy -- and everything else. There's nothing quite like their "Waiting for Guffman, " "Best in Show, " "A Mighty Wind, " and the duo's latest, "For Your Consideration, " which opens Friday. For lack of a better name, call them "milieu comedies." Guest and Levy also act in them, and Guest directs.

They were in Boston last week to promote the new movie. Levy tended to defer to Guest, but not much. Both were dressed in High Hollywood Casual: jeans, blazers, open-neck shirts. That was the only thing casual about them. They fielded questions like two very serious ping-pong players using jokes for paddles.

"Our stuff isn't broad," Levy said, unlike typical Hollywood comedies, "which are hinged around three major set pieces." Their films, Levy said, are "all about characters. Honestly, it's character work. It's all got to be grounded."

Guest agreed. "Along with the comedy, we do attempt to write about other parts of the human experience."

Those parts of the human experience include community theater ("Guffman"), dog shows ("Best"), folk music ("Wind"), and now the hoopla surrounding Oscar season. But Guest and Levy's take is offbeat and their characters are often somewhat crazed. Take Corky St. Clair, the flamboyant stage director in "Guffman." Or the Weimaraner-owning yuppies whose obsessive search for the proper chew toy nearly tears apart their marriage in "Best in Show."

Besides focusing on a specific milieu, these films are notable for featuring the same ensemble of actors. "For Your Consideration" looks at what happens when the stars of a low-budget period drama, "Home for Purim," become the object of Oscar speculation. They're played by Catherine O'Hara and Harry Shearer .

Other ensemble regulars in "Consideration" include Parker Posey , Fred Willard , Bob Balaban , Ed Begley Jr. , and Michael McKean . The one notable addition to the troupe is Ricky Gervais , co creator and star of "The Office" in its original BBC incarnation. .

"For Your Consideration" marks a departure for Guest and Levy. It's the first script they haven't written in mockumentary style. Their comedies trace their lineage back to the greatest (and loudest) of mockumentaries, "This Is Spinal Tap, " written by Guest, Shearer, McKean, and its director, Rob Reiner.

The new movie is also the first time Guest and Levy have tried to balance comedy with more emotional material.

"We very much intended to show the poignant aspects of this story," Guest said. "And Catherine O'Hara, being a great comedian but also a very, very good actress, was the perfect person to be the center of this story."

O'Hara gets more than her share of laughs in "Consideration" as Marilyn Hack . But in playing an aging actress whose character in the film-within-the-film is dying, she had to be willing both to expose herself emotionally to an unusual degree and let herself be shot far less flatteringly than even a comic actress is used to in Hollywood.

"When I read it, I got a little scared because I thought, 'There's nothing inherently funny about this character,' " O'Hara said in an interview at the Toronto International Film Festival in September.

"The facts were in the script," O'Hara said, "so then I just had to work on who this woman would be. I started with 'workhorse actress.' I'm there for the work. I'm there to do whatever I can to fulfill the writer's and director's dreams. It's not about me. I must honor my character. I must honor the story. It's not about me."

O'Hara made a point of saying "facts" in the script rather than "words." The screenplays Guest and Levy write are fully worked out, but within the structure the actors are left free to improvise all their dialogue.

"We write a backstory for every character," Guest said. "In the case of the actors within the film we wrote down for them all the plays they'd been in, all the TV shows. . . . Every scene is very much structured in terms of emotion and information. That ends up being about a 25-page outline. Then I discuss the parts with the actors. It's then up to the actors within that scene to get that information across, but there's no dialogue written and there's no rehearsal."

How the actors respond to such freedom varies considerably. Scenes are shot in only two or three takes, Guest said, and for each one he likes to come up with new dialogue. Levy, who has an improv background thanks to his start at Second City Toronto , said he prefers a more conservative approach.

"If you hit on something that feels right and seems funny," he said, "there is a bottom to the well in my case. If it works, you'd be crazy not to use it when you go in for coverage and start doing close-ups."

With so few takes and a cast that works together regularly, Guest said, shooting the comedies usually takes just four weeks. It's the preproduction that's time-consuming.

"It's about five, six weeks working out the stories and the characters," Levy said, "then it's about eight weeks actually mapping out the script."

Do Guest and Levy have a drawer full of future milieus to tackle?

"There is a drawer," Guest deadpanned, "but there's nothing in it. Truly. A lot of filmmakers have multiple things in development, but it takes me a year after we finish to come up with another idea. If something pops into my head, I call Eugene. I say, 'What about this?' And he says, 'I'm busy.' "

In the past, they've considered doing a Western, a film about a small-town election, and a period movie. A fatal obstacle to making the last one was the dialogue, Levy said. "I don't know anyone who can do improv in Latin."

What with its subject matter, "For Your Consideration" raises an obvious question. Have Guest and Levy pondered what their own Oscar speeches might sound like? After all, the New York Film Critics Circle named Levy best supporting actor in 2003 for his performance as easily stressed folk singer Mitch Cohen in "A Mighty Wind."

Guest made a face. Levy beamed.

"I've heard Chris's speech," he said, turning to Guest, "and I hope you get to give it some day."

"You heard it because you wrote it," Guest said.

"The first line," Levy said, "would be, 'What the hell were people thinking?' "

Mark Feeney can be reached at mfeeney@globe.com. Scott Heller of the Globe staff contributed to this story from Toronto.