Bill Irwin's 75-minute The Harlequin Studies at the Signature didn't do that for me, unfortunately. The "studies" in his title makes his clowning much too dry and academic for my taste. Scholarly, half-jesting references are made to a meeting of Archetype and Individual when all one yearns for is the custard pie. The modest little sketches are textbook stuff: Mischievous Harlequin fools his gullible old master Pantalone once again ; Harlequin juggles plate; Harlequin juggles hat; Harlequin walks down invisible stairs; Harlequin falls in love with Wrong Girl. Alas, we see the jokes coming in a dull enchantment zone occupied only by rarefied, overindulged clowning. Everything is in muted good taste. Even when Mr. Irwin is vulgar, he farts quietly.

That said, I must report that the audience as a whole seemed to enjoy Mr. Irwin and his fellow clowns (who tumble a lot). Only a pocket of malcontents surrounding me, as if placed in separate seating for the Anti-Life, failed to respond to his watery reconstruction of traditional commedia dell'arte (cf. commedia , 1550-1800). The vitality and daring of truly spontaneous improvisation-a glorious liberty and individualism that can bring a theater to uncontrolled uproar-are the magical qualities that keep the commedia dell'arte tradition alive. Mr. Irwin, in partnership with the unpredictable extrovert David Shiner, was wonderfully funny in Fool Moon on Broadway. But his lackluster Harlequin Studies needs a red nose, or the child's infectious, unstoppable howls of laughter.

But what makes me laugh-and what makes you laugh-are mysterious things. Or, as Laurence Olivier once put it charmingly about an admired fellow actor who was playing a comic role, "He's as much humor as a dead baby in an open coffin." We can theorize about laughter a thousand ways, as Freud and Bergson did, but in the end, why we laugh when we do is an unsolvable mystery. I was once fortunate enough to interview one of the greatest comics in England, Ken (Doddy) Dodd, whose manic, vaudevillian genius was informed by his own very serious studies into the history of laughter. He was an intellectual of humor who once defined Malvolio as the sort of man who used to stand up in a strip club and shout, "What time do the jugglers come on?" He even wondered during our meeting why we make the sound of laughter. "I mean," he suggested in all seriousness, "why doesn't your nose light up instead?"

There's no answer to that. But Freud's theories of comedy were no use to Doddy as a performer. "The problem with Freud," he explained, "is that he never played the Glasgow Empire, second house, Saturday night." The old Glasgow Empire was the fabled graveyard of comics. No fancy Freudian theories could help the entertainer who was brave or foolish enough to go out there and face the mob.

And yet there are people who can make us laugh on sight. Bill Murray makes me laugh without actually doing anything. Jokes per se tend to embarrass me. I always worry I won't get the joke. Ricky Gervais, the brilliant "anti-comedian" who created the BBC America import The Office , makes me laugh precisely because the character he plays to sly deadpan perfection thinks he's funny but isn't. I've never found Jerry Seinfeld funny. Steve Martin-always; Chris Rock-no. I prefer Keaton to Chaplin, funnily enough. Anyone who slips on a banana peel is funny. Donald Rumsfeld is funny. So is any Preston Sturges movie, any time. Oscar Wilde isn't as funny as he would like to be. (He's witty .) Margaret Cho-no; Jonathan Swift-yes. I threw in Swift to be impressively Swiftian. And all the loved, eccentric performers from my childhood, including this eternal exchange between a drunk and a man nursing a cardboard box under his arm who has just returned from Egypt with an elephant:

"Where do you keep the elephant?" the drunk asks him.

"It's in this box."

"I thought I heard a rustling!"

Which brings me to my favorite, Eddie Izzard, the transvestite wizard who had us all in stitches during his new Sexie touring show that stopped off at the packed City Center. Times have changed! I first saw him testing the waters hilariously seven years ago at the Performance Space 122 downtown, where he wore high heels, quite modest PVC trousers, green nail varnish, red lipstick, perhaps a dab of rouge. But Uptown Eddie at City Center was wearing knee-high spiked boots, fetching fishnet stockings, a sparkly black skirt slit to the waist, plus a form-fitting bustier, red lipstick (of course), eye makeup that was a little heavy on the kohl, a stylish spiky haircut with great blond highlighting and all of it tastefully set off with diamond earrings. But this is the point:

He's still our Eddie! Success in America hasn't spoiled him in the least. He's always looked like a doll. Why does he dress like a woman? It's what he likes to do. He's in artful costume! I wrote when I first saw him that his surprising costume of sexual ambiguity is as traditional and unthreatening as the white-face clown's.

Now here's a performance that brings an audience to the point of mad laughter while seeming to be utterly, spontaneously improvised. Mr. Izzard doesn't tell jokes; he isn't hostile. He doesn't ask to be liked or loved (but he is). He seems to have no political agenda (though he's clearly a libertarian). He's an absurdist storyteller conjuring up insane stage pictures. He's a literate fantasist in the noble tradition of rambling on about absolutely anything that comes to mind-including using false breasts as earmuffs, the agonizingly slow pace of archaeologists, stabbing children on planes with forks, the unbelievable popularity of balsamic vinegar, the retelling of Homer's Odyssey from the vantage point of a water skier, dog racing from the point of view of the greyhounds, Neanderthal man decorating a house and-if I heard it right-the sound of cats thrown out of a car window.

He's such a master of the unpredictable that he pretends to get lost. "Where was I?" he asked at one point, peering out at us. "So … yes. But. O.K.! Fifty thousand years ago. Stay with me …."

There's a link, incidentally, with the stream-of-consciousness comedy of one of Britain's music-hall greats, Frankie Howerd, whose insane diversions and asides gave you the impression that he'd lost the plot, too. "No, don't. Well. Yes. I mean," Frankie would say. "Pull yourselves together! You'll make me a laughing stock …. "

But there's no one like Eddie Izzard. I don't know of any performer who's as unique or as funny. His comic genius is that his surreal, near-cozy chats liberate us to such dizzying heights that we don't want to pull ourselves together at all.

What is it about him that has us convulsed with sustained laughter about such amazing things as homeopathic lawnmowers and the siege of Troy? He has no political or social agenda. This British comic (who's a star in England) doesn't belong to the coarse Comedy Store school of wiseacres and vulgarians. Nor is he a Symbol of Our Times, like smug Jerry Seinfeld. His eccentric choice of material rises above mere topicality. He's an un-American activity in many ways, yet Americans love him. He doesn't tell jokes, exactly. He appears in semi-drag, suggesting the feminine, but he isn't a drag artist. Who, or what, is he?

The late John Osborne (of Look Back in Anger ) defined the great vaudevillians he worshiped as members of an elite warrior class. Laurence Olivier famously played Osborne's failed comic, Archie Rice, in Osborne's The Entertainer . It was said that Olivier had gone downmarket by playing the seedy working comic instead of his more customary kings and heroes. But, in truth, he was playing a hero-the warrior-comedian whose parting, defiant words in The Entertainer are actually inscribed on Osborne's tombstone:

"Let me know where you're working tomorrow night, and I'll come and see you ."

They're the unforgettable words and challenge of the Always Judged. And the warrior-comedian is judged more than anyone, night after night, at the mercy of hecklers and drunks and know-it-alls, standing or falling alone. Eddie Izzard-the name itself is unusual, jaunty, suggesting wizardry-doesn't, at first sight, appear to be a natural warrior, what with the rust-colored satin outfit, the red nail polish, the discreet jewelry and the four-inch stacked heels.

Well, it suits him! He looks like a doll. He's an unthreatening presence. He possesses such a pleasant stage personality that he creates an immediate rapport with the audience. At the same time, he's secretly artful. He doesn't quite "belong." He might be a friendly alien. He's really wearing a costume-as traditional and as pretty as a white-faced clown's.

Eddie Izzard, the wizard, is the direct contemporary link to the fabled music hall whose greatest artists in England have never been, strictly speaking, normal. John Osborne's favorite musical hall genius was the risqué Max Miller, who wore a satin coat of many colors, like Joseph. My favorite, worshipped since childhood, was Max Wall, who wore black baggy tights and a leering look on his face like a demented professor. The manic explosiveness of John Cleese owes a debt to Max Wall. Eddie Izzard owes a small debt to Monty Python.

He's a surrealist storyteller. He builds mad stage pictures of Noah's Ark and Sean Connery, like a comic Magritte. He makes the mundane world oddly interesting, and the surreal normal. He anthropomorphises the strange phobias of pilot fish, the unconscious life of birds who dream of walking, and the terror of blades of grass about to be cut ("Keep your heads down, lads!"). He enjoys the disconnected Pythonesque silly, and so do we.

He doesn't do segues, but there is no need. In a show that seems to be brilliantly invented on the spot, he proceeds as if he's just popped in for a cozy chat about anything that comes to mind. You therefore can't anticipate him. He might jump-cut from elderly ladies who tell us their age-"I'm 82! I'm 82!"-to the Grim Reaper who modernizes by turning in his scythe for a power mower.

Mr. Izzard is an original, all right. Which other comedian could we even imagine creating a picture of an Achilles who actually has an Achilles' heel? His latest show at P.S. 122, aptly entitled Glorious , is another of his semi-discreet test runs. He seems concerned for some reason that his English humor might not travel. In which case, he's the most relaxed concerned comic we know. His glorious comedy isn't specifically English, except, possibly, when performing Shakespeare in a Birmingham accent. He's an accomplished mime, and as universal as one. Called back for an encore, he returned with his signature impersonation of a bird flying in a plane who's seen by astonished, jealous birds outside …

I'm happy to say that I wish Eddie Izzard's 90-minute tour de force had gone on longer. On the other hand, I regret that I couldn't have been more relieved when Christopher Kyle's new saga about aging, foolish yuppies, Plunge , drifted to its sorry end.

In the first place, I've no wish to see yet another play that takes place in the Paramount hotel. I've never got to know a hotel so intimately without staying there. Much of Douglas Carter Beane's satire of success, As Bees in Honey Drown , is set in the Paramount lobby, where comfort is considered unstylish. Various dire scenes in Plunge -"coming here with a married man, this is totally not me"-are set in a cramped bedroom of the Paramount where minimalist cells with one flower are considered chic.

Plunge is totally not me, and it will be totally not you, too-unless the lifeless, plotless, domestic little dramas of deeply uninteresting, adolescent 30-year-old baby boomers are to your taste. I doubt that very much. Mr. Kyle, the author of The Monogamist , left me in a sour mood, as perhaps you can tell. Or, as one of his vacant thirtysomething characters puts it: "You are so not amusing me right now."

Everything in this lame, inconsequential piece reminds us of something else-a bad movie, an episode of Friends , the yuppie oeuvre of Richard Greenberg. Apart from the Paramount, Plunge also takes place during yet another Labor Day weekend house party in a restored farmhouse in Connecticut. It's old hat dressed up in Generation X clothes. Val, a sullen environmentalist who's taken a job in the Con Edison legal department, confesses-shock!-she's become a lesbian. Her Harvard-educated husband, Harris, who's stupid, is upset. Superficial Clare, the hostess and vice president of her father's investment bank, slept with Harris, but nothing happened. Now she's sleeping with Jim, the office temp and free spirit who falls inappropriately in love with her. Clare is also about to sleep with her old college buddy, cynical Matty, who might be gay and is training to be a priest in order to inherit a fortune from his mom, and …

Plunge is one of 14 plays commissioned from Playwrights Horizons by Steven Spielberg's Amblin-Dreamworks. It's everything that's wrong with movies.