Chekhov on the Lawn; Play by Elihu Winer. Directed by Mr. Winer. Starring William Shust.

The time is April 17, 1900. The place is Anton Chekhov's home in Yalta, on the Black Sea. The special occasion is the Moscow Art Theater company's visit to Yalta. It has come to perform part of its repertory (including "Uncle Vanya") for its celebrated author, who has left Moscow for reasons of health.

Elihu Winer imagines that, on the afternoons of their visit, Chekhov regales his colleagues by reciting stories and anecdotes. Hence Mr. Winer's "Chekhov on the Lawn," at the downstairs Theater East.

Moving in leisurely fashion about a patch of garden, William Shust elaborates on the incident with an attractive and gracefully animated performance as Chekhov. The result is a kind of chamber recital, an intimate entertainment relying for its effects on the rich humanity of the stories as projected through a sensitive player's versatility.

The mood of the dramatic miniatures ranges from comedy to tragedy and frequently involves children. Here Chekhov's tenderness and concern are at their most poignant. A beggar's ravenous child is fed oysters by some careless men-about-town. A more privileged youngster nevertheless experiences the disillusioning shock of adult betrayal. Other narratives involve fantastic cat-and-mouse games, the fatal effects of a minor bureaucrat's persistent servility, romantic suggestibility and susceptibility, and the tribulations of an urbanite's summertime season in the country.

Through the imagined but authentic discourse, Messrs. Winer and Shust pay tribute to the hero of the occasion and capture the atmosphere of a bygone artistic milieu. Visitors to Theater East find themselves hospitably welcomed and pleasantly entertained on Chekhov's turf. An Evening With Dave Allen

Late-night television watchers in North America may have become acquainted with Dave Allen, a London-based Irish comic with a mischievous smile, well-tempered urbanity, and audacious line of patter. In his TV appearances, Mr. Allen includes sketches along with armchair commentary. At the Booth Theater, where he makes his Broadway stage debut, he dispenses with skits and concentrates on stand-up monologue.Two hours of it with one intermission.

Strolling casually about the stage, Mr. Allen covers a range of familiar foolishness as he takes potshots at the nonsense of the contemporary scene. Employing what he calls "lateral thinking" (and using the mike for sound effects), he goes after TV commercials, idiotic signs ("Bus Stop -- No Standing"), and medically prescribed pill popping. He explores usages ("Take the car for a run"), slams statistics, and attacks matriarchal discipline. He is often very funny.

In Allen's iconoclastic vein, he reminisces devastatingly on his primary school convent education and retells Bible stories in his own irreverent fashion. Like some other funnymen over the years, he apparently cleans up his act for the tube. Or perhaps he coarsens it for the stage. In any case, "An Evening With Dave Allen" is liberally supplied with what used to be known as locker-room humor before the locker room moved into the drawing room. The show is not an entertainment for all tastes.

The British press has described Allen as "London's most notorious wit" and as "Great Britain's most literate and intelligent comic." The qualities are variably and articulately on display at the Booth.