Watching "The Play What I Wrote," which opened last night at the Lyceum, is like spending two hours with the puppies in the pet store window. Sean Foley and Hamish McColl, the British comics who make up the double act The Right Size, are constantly leaping, falling, yelling, barking and getting slapped around by Daryl Hannah.

The duo's energy is unmistakably canine, as is their voracity. Having burrowed among the roots of twentieth century comedy, they can't wait to lay their treasures at your feet. The dominant influence is vaudeville, but traces of later styles pop up as well. Detractors will point to any number of limp gags and stale clichés in their presentation. But when the show works, which is often, it is deliriously funny.

There's a plot, for those who need a plot. Mr. McColl wants to quit the team and put on his own plays, particularly the French Revolution epic "A Tight Squeeze for the Scarlet Pimple." To preserve the act, Mr. Foley tells Mr. McColl the American impresario Mike Tickles (think Nichols, who is one of the show's backers) wants to produce his play on Broadway. The resulting show is a mix of the two. It ends with a performance of Mr. McColl's play, starring a different mystery guest each night.

In the British incarnation of the play (which won raves on the West End) Mr. Foley and Mr. McColl explicitly linked their performances to Morecambe and Wise, the kings of English comedy from vaudeville to the television age. Though the references are much less obvious in New York, the earlier duo's influence is still apparent. George (sic) Braden, who wrote scripts for Morecambe and Wise, shares writing credit for this show with Messrs. Foley and McColl. This helps to account for the dynamic between the two of them.

Mr. McColl is a straight man who's funny. He looks like a stocky Tony Blair, a quivering enthusiast who is never far from exasperation. He drapes himself in the tricolor and proclaims, "I am France, and parts of me are revolting." Later he announces, a propos of nothing, "As Shakespeare once said after a big lunch, 'We don't need another hero.'"

His partner, Mr. Foley, is tall, relentless, sweat-soaked and indestructible. As he crashes around the stage, the amount of abuse he suffers and energy he expends is tremendous. Mr. Foley doesn't just jab at Mr. McColl with a joke, he punctuates the joke with a kind of swooning knee-bend and mug to the back of the house. He manages to be the funny one and poke fun at the idea of being the funny one at the same time.

The duo is joined by their impervious sidekick, Toby Jones, who is a cross between Mickey Rooney and a pug, and who steals nearly every scene he's in. Mr. Jones plays all of the secondary parts, including Daryl Hannah, a role he essays in blonde wig and blue teddy; Mike Tickles, for which he dons a disco-era getup (no explanation given); and, in gaudy bald wig, Gerald Schoenfeld. Mr. Schoenfeld is the Chairman of the Shubert Organization, which makes him the owner of the Lyceum. In act one, he storms onto the stage to berate the duo for not giving the audience what they want, firing a pistol at them for punctuation. Then he leaves to shoot himself in the foyer (pronounced, with an extravagant sweep of the arm, "fwoy-ayyy").

On press night, the damp exertions of Messrs. Foley, McColl and Jones found their counterpoint in the mystery guest, Kevin Kline. He trod the boards with cool hauteur, summoning a regal bearing that made him Margaret Dumont to their Marxes. Mr. Foley called him Calvin Klein and handed over his underwear. Mr. Jones pretended to be Patsy Cline, donning a star-spangled outfit and history's worst brown wig to warble "Crazy." The sniping will be familiar to anyone who's seen a Hasty Pudding roast.

There's plenty of old material in "The Play What I Wrote" - jokes that fall flat either because they're no good or because they've been run into the ground. There are also plenty of moments when the gap between the American and British senses of humor yawns over the footlights. But director Kenneth Branagh and his manic cast dare you not to laugh.

The show's detractors are undoubtedly right to call the "mystery guest" feature a gimmick. Any gimmick that yields the spectacle of Kevin Kline dancing the can-can in a hoop skirt the size of a Steinway passes muster with me.