The Woolly Mammoth Theatre Company, a new addition to Washington's experimental theater scene, is making its bow with a double bill -- an improvised, nonscripted exercise and a one-act play by Mark Medoff, the playwright whose "Children of a Lesser God" is a Tony award-winning Broadway hit.

The Woolly Mammoth troupe hopes not to become extinct as its namesake did. Judging from its first offering for Washington audiences, the company deserves a chance for survival in the precarious world of small theater troupes. The premiere was not an undiluted success but did hold promise.

First of all, let's dismiss the improvisation, which is aborted in mid-flight by a shot. This leaves a corpse on the stage. The corpse, as puzzled as the audience, finally asks: "Why did you do it?" The improviser tries to explain that she was bored with the scene.

The trio on stage -- Kim Langford, Howard Shalwitz and Lola Borja -- attempts to retrive the story line but it ends up with an ironically appropriate title -- "Fits and Starts."

Experimental theater companies seem determined to take their lab exercises in improvisation before an audience. Too often this is a mistake, at least for general audiences. There may be some instruction in seeing actors respond on the spot with subtle shifts in characters.But it isn't that satisfying or exciting to the average theatergoer.

The company's production of Medoff's "The Froegle Dictum" redeems the evening. It is a difficult play -- hilariously absurd yet somehow poignant and touching.

Stephen Wallace Haines, a lost vacant look in his wide-eyed stare, gives a strong performance as Al, who wants only to be left alone to commit suicide. He keeps botching the attempts both by rope and a tainted bologna sandwich.

One of the reasons Al may want to end his life is that he is constantly being assaulted with homilies of positive thinking delivered by Ronnie, who shares the apartment. He also endlessly quotes dictums from Froegle, a philosopher of optimism. And there is a Mandy, Ronnie's live-in girl, who is unbelievably naive of mind and desirable of body. Mary Ruberry is splendid as Mandy. She tosses away her absurd observations with an ingenuous air and innocence.

Mike Johnson and Jan Solidinger round out the cast in the supporting roles of Ronnie and Harriet, the plain-faced gal provided by Mandy to cheer up the depressed Al. Johnson is just fine as the cheerful quoter of philosophical cliches. Soldinger's Harriet might be more affecting if she were given more spirit and not interpreted as a flat, monochromatic character. Roger M. Brady, the company's artistic director, exhibits a sure hand in pacing and stage exchanges.

The Woolly Mammoth Company has been fortunate in finding theater space in the hall of the Church of the Epiphany at 1317 G St. NW. The troupe will perform its double bill at 8 o'clock tonight and 7:30 p.m. tomorrow. Next week there will be performances at 8 p.m. Wednesday through Saturday, with a Saturday matinee at 2 p.m. and a Sunday performance at 7:30 p.m.