WHAT CAN YOU SAY about a three-act play that's unrehearsed? That it was brilliant and beautiful, I suppose, but in the case of A Three-Act Play That's Unrehearsed, the third act of which is at the Loeb Ex tonight, such a statement would have the disadvantage of being patently untrue. I enjoyed A Three-Act Play, however, much to my surprise and for reasons that remain a bit obscure.

At times Thursday night's improvisation was extremely dull, but it had its moments, too. The two performers, who introduced themselves as Steve and Paul, announced several climaxes in the course of the evening, the most convincing of which was probably Steve's threat to play a love scene with a friend of his. She happened to be one-tenth of the audience, which had long since demonstrated that it thought it could out-act the actors, which was quite possibly the case.

Steve also engaged in a brief discussion of the changing nature of theater with an interested spectator, who expressed the theory that improvisations are the wave of the future, and he played magician for a while. Paul was more relaxed than Steve, which enabled him to carry the show when Steve got nervous. Paul played the Narrator and The First Walker.

Only two members of the audience left early. One of those exited with some reflections on Lewis Carroll and life, while the other's departure prompted a discussion of his character and future course ("He's begging for change under a streetlamp on Brattle Street!" "He's copping out!"). There were only ten spectators to begin with, of course, mostly friends of the actors, and nobody ever found the bird Paul had promised would be the meaning of the play. But an 80 per cent retention rate isn't bad, and no doubt the bird is warbling a song somewhere.