Just when a number of companies in town are engaged in the feverish pursuit of "a new theater," along comes a clown named Bill Irwin to send up their efforts in a dizzy, delirious and perfectly delightful show, "The Regard of Flight."

Call it coincidence. Call it comeuppance. Call it whatever you want, but trot right off to Arena Stage's Kreeger Theater, where Irwin and his two companions in nonsense will be appearing through Jan. 12. This is as deft a piece of mirth making and spirit raising as Washington has seen all year.

It helps to have a general knowledge of the avant-garde pretensions that are being skewered, but it is by no means mandatory. "The Regard of Flight," which opened last night, is first and foremost 75 minutes of pure fooling around, but performed with such invention and dexterity that it becomes high art.

If you had to classify Irwin (which is rather like describing the shape of quicksilver), I suppose you'd say he belongs to the school of helpless clowns -- those upon whom the fates, banana peels and various curmudgeons are forever visiting misfortune and indignity. An unidentifiable, but irresistible offstage force, for example, is determined to prevent him from indulging in an exhibition of soft-shoe. Each time Irwin begins his dance, he finds himself inevitably sucked toward the wings. The more he picks up the steps, the more he finds himself drifting leftward. Panic inundates his face. Then his legs whip right out from underneath him, as if they were pins drawn to a magnet. It's all he can do to scramble back to the center of the stage.

In "The Regard of Flight," he presents himself as a hapless pioneer, forging "a contemporary performance piece in a postmodernist construct" with the assistance of a deadpan pianist, Doug Skinner, who is as nimble of finger as he is of wit. Skinner calls out the orders -- "dance segment," "kinetic imagery segment," "on-stage costume change," "first homesickness song" -- and Irwin, obliging soul that he is, tries gallantly to keep pace. But booby traps await him at every turn. If he goes to put on a vest, the vest fights back. Let him open a steamer trunk -- he's bound to tumble in. He can't keep tabs on his left shoe. And, naturally, precisely when he's shortest of breath from darting about the theater, he's required to sing "Home in Pasadena," which he does trippingly until he nearly collapses from lack of oxygen.

As if that were not enough, he has a persistent little nemesis in the person of M.C. O'Connor, who dogs him at every turn, presses him for explanations, swats him in the puss and even forces him to try his hand at Shakespeare. O'Connor, who looks as if he's wearing Groucho glasses even when he isn't, perceives symbols and significance everywhere. "So you're a prophet," he says to Irwin, accusingly. "No, nonprofit," replies Irwin innocently.

You see, all the while the three performers are engaging in their nutty vaudeville antics, they are tossing off the platitudes and pieties of the avant-garde. Skinner periodically takes to the podium to deliver arcane commentary on such topics as "environmental staging" and "the deep-seated mistrust of the proscenium." At one point, O'Connor, glaring like a critic, wants to know what Irwin thinks he's doing. "I am trying to be here in this space now," says Irwin with a hint of pique -- all, incidentally, he ever dares allow himself in the way of bad temperament.

Or consider this exchange between Skinner, who is also a ventriloquist, and his dummy. Skinner: "Our goal is to create a new theater." Dummy: "Can't you just redecorate this one?"

You don't want it to end. But if these three know their vaudeville, they also know its cardinal rule: Leave 'em wanting more. "The Regard of Flight" comes full circle after an all-too-brief hour. The last 15 minutes is devoted to a handful of self-contained "clown bagatelles."

Mocking one-man orchestras, Skinner plays a nutty overture on the piano, xylophone and one of those silver bells normally found on the front desks of hotels. Irwin and O'Connor, waiter and chef, grapple titanically with a pot of noodles. Then, activating a tape recorder, Irwin demonstrates the art of disco dancing. Before long he's shaking his body in cool abandon. His arms are flapping and his head is bobbing and, ohmygod, he can't stop. He's being victimized by the beat. Clearly, there is no safe haven for this man!

Perhaps that's why he chooses to spend the final minutes of the show as a marionette. The grace with which he will convince you that his body is attached to invisible strings is remarkable. But more than that, the image is extraordinarily apt. Throughout the show, others have been leading him on a merry chase -- stage right, stage left and all around the house. Why should that change now?

Some people are born manipulators. Bill Irwin was born to be manipulated.

The Regard of Flight. Written by Bill Irwin. Original music, Doug Skinner. Set, David M. Glenn; lighting, Nancy Schertler. With Bill Irwin, M.C. O'Connor, Doug Skinner. At Arena's Kreeger Theater through Jan. 12.