On stage, Bill Irwin is an astonishing bag of tricks -- disappearing into a trunk, getting so tangled in a vest one worries for his safety, pratfalling with the grace of a gazelle. "The Regard of Flight," the show that he and two confederates have brought to the Kreeger Theater for a short run, follows in the spiritual footsteps of the Flying Karamazov Brothers, Foolsfire and Avner the Eccentric: theater on a banana peel.

These entertainers spring from a crazy-quilt heritage that ranges from the Marx Brothers and Red Skelton to Samuel Beckett. Someone (probably a reporter) dubbed them The New Vaudevillians, which means, basically, clowns who went to college. "It's a handy phrase and so it won't die," said Irwin. "We disclaim the term but we end up using it."

They are also, especially in Irwin's case, clowns with a conscience, concerned not just with getting laughs, but with the kind of laughs they get. Their work is suffused with a kind of zany, subversive political consciousness and irreverence. Furthermore, they are very funny.

Off stage, Irwin seems rather pensive and not just because he hasn't had breakfast. He doesn't put funny hats on his head or make faces for the photographer. He looks like a very fit, slightly tense 35-year-old, with close-cropped strawberry-blond hair and blue eyes. He proves you no longer have to look funny to be funny.

Irwin is probably one of the few people who have attended both Oberlin College and the Ringling Bros. and Barnum & Bailey Clown College. After years of living the hardscrabble life of an uncelebrated artist, performing with the Pickle Family Circus and the Oberlin Dance Collective, he was given a MacArthur Fellowship in 1984 -- $180,000 spread over five years. He is the first performer to receive the no-strings-attached, manna-from-heaven grant, but it has not been all serendipity.

"I've never had less money than I do right now," he said with a befuddled air. It seems, well, he had to pay off some debts, and he spent quite a bit on his last theater piece, "The Courtroom," and there are modest support payments to his ex-wife and then he had to buy new costumes and so forth for this run of "The Regard of Flight," and the net result is no net. "I guess I lost touch with some of my frugal habits, too," he said. This is one actor who'll be taking the subway for a while.

He owns no property, not even a car. "I have, uh, a sort of political problem with, uh, wealth," he says hesitantly, as though it sounds presumptuous for him to even think about the possibility of being, uh, rich and famous. Although there have been these television people talking to him, which he thinks he'd better not talk about because probably nothing will come of it. But the prospect of prosperity, combined with being of an age at which you start to think about things like buying a house or having children, have made him worry about it all -- about the loss of innocence that could come hand in hand with worldliness and how that could drain the spirit out of his work.

"I worry sometimes that I don't have the kind of center of gravity that a grownup should have," he said.

Irwin is from California but moved often as a child because of his father's job as an aviation engineer. Everyone in his family has an interest in theater in one form or another. As children, he and his sister had a comedy act and made a big hit with "The Ned Bullivan Show," a parody of "The Ed Sullivan Show," on which they played the host and all the guests.

He dropped out of the theater program at UCLA to join the less traditional California Insititute of the Arts and left that a few years later to follow its director, Herbert Blau, to Oberlin. (Another Blau student was Michael O'Connor, who plays the drama critic in "The Regard of Flight." Doug Skinner, the brilliant accompanist and ventriloquist in the show, was another Oberlin student.)

Blau was not just a teacher and director, but a guru. "We used language, but the training was rigorously physical, seven hours a day," O'Connor told Mel Gussow in a New Yorker profile of Irwin. "It was very serious sacramental work. We were asked to do these strange things that make you very vulnerable. The basis of the technique was something called impulse work. This meant suddenly moving your body at the highest rate of speed and following any kind of impulse."

"The Regard of Flight" punctures, with gentle relentlessness, all the pomposity of "the new theater." Skinner, who looks like an assassin masquerading as a professor, lectures from one corner of the stage, referring to "the empty polish of conventional theater" and the "cantilever action" of Irwin's clown's "lean shoes" and at one point translating Irwin's words into perfect French.

Along the way Irwin studied mime, dance, tai chi, gymnastics, juggling, trampoline and elephant riding. He is respectful of the old techniques, never substituting intellectual tricks for real skill. He has spent many hours watching old masters on film and in person, from Keaton and Chaplin and Marcel Marceau to a clown in his late sixties named George Carl, who generally performs in striptease clubs between strips. Carl, whose comedy is entirely physical, is one of Irwin's major influences.

"I spent a lot of money going to see him," Irwin said. "Sometimes I'd ask people to come who I knew could afford to pay. Like once I invited Joseph Papp and his wife. When he picked up the check I felt kind of terrible." (But not too terrible.)

"The Regard of Flight" was first performed in 1982. Since then Irwin has created "The Courtroom," which he says was only partly successful, had a small part in "Accidental Death of an Anarchist" and appeared in a "dance theater" piece that required him to float above the stage on wires. He appeared in one movie, "Popeye," and last summer did two plays at the La Jolla playhouse with director Des McAnuff, playing the central character in Bertolt Brecht's "A Man's a Man" and the pathetic schoolteacher in "The Sea Gull." He recently auditioned for the part of Laertes, of all things, in the Kevin Kline production of "Hamlet" at Papp's Public Theater; he doesn't think he got the part. His major goal at the moment is to be cast in a production of "Waiting for Godot," timed to coincide with Beckett's 80th birthday next year.

"All my basic instincts are an actor's," he said. He wants to do more plays, combining his clowning and "popular entertainment" skills with his theater sensibility -- a move he delayed for a while after getting the MacArthur grant.

"I was in a quandary," he said. "The grant seemed in a way a mandate to develop more original work, like this show. But after a while I realized that it is their last intention to tell you what to do . . .

"Sometimes I think, 'What have I done with 35 years of my life?' On a good night it means something to the audience. But an hour and a half later it's gone. There's no question that I want to be involved in theater. The question is in what way . . .

"After all," he said later. "You can't fall down all your life."