THIS IS A TOWN of talk, and talkers. Spalding Gray capitalizes on that in "Interviewing the Audience," the unusual theater piece that concludes his highly successful six-week stay at New Playwrights' Theater.

"Interviewing" is an eccentric, demanding evening, different each time because its success depends so heavily on the audience.

Gray's task is finding the chinks in the armor, and he does so ingeniously. Here he's playing an avant-garde talk-show host, always the ingenuous outsider, politely insisting on having everything explained to him.

Probing delicately, challenging bluntly, Gray is a chillingly good listener and a master of the well-timed unexpected question. How people resist is as fascinating as the details they unwittingly reveal.

To open "Interviewing," New Playwrights' invited a "celebrity audience." Gray interviewed two journalists, a businesswoman and an actor, with mixed results. The journalists, Washington Times veteran gossip columnist Betty Beale and Washington Post political writer James R. Dickenson, let slip some funny observations, but they are practiced talkers, and both cleverly blocked Gray whenever he approached a tender spot.

But when Gray called on corporate analyst Bettie Reilly, he showed what "Interviewing" could be. Unsure, giggly, awkward under Gray's sometimes discomfiting probing, Reilly revealed more than she had intended about her past and present. Unfortunately, Gray chose to wind up with David Warrilow, an actor colleague who prated on endlessly about his craft and an outlandish religious cult, effectively excluding the audience and ending the show on a stale "Tonight Show" tone.

Though Gray gets permission from his subjects before the show, an unsettling sense remains -- that anxious, forgot-your-homework fifth-grade feeling: "Please don't let him call on me!"