Act I, Scene I: Smoking a cigarette, the father enters. His teen-aged son immediately rushes to stub out his own cigarette and hide the ashtray. The father appears not to notice.

Such everyday contradictions are the delight of the Allen family -- Terry (father), Jo Harvey (mother) and sons Bukka (the smoker) and Bale -- who have come from Fresno, Calif., to perform "Do You Know What Your Children Are Tonight?" at the Washington Project for the Arts.

It really is their play. They wrote it, directed it, star in it, and designed and built the set.

Here for a WPA series of works on the family, it is perhaps less a play than a sort of family talent show. The Allens recite their own poetry. Bale and Terry play original songs on the piano. Slides of friends -- and of Bukka's and Bale's drawings -- are shown on the wall. WPA executive director Jock Reynolds, who had worked with Terry in San Francisco in the mid-'70s, commissioned the family to participate in his series, "The Family as Subject Matter in Contemporary Art," which has included photography, films, video and a poetry reading.

The play, which will have its final performance tonight at 8, is the family's first collaborative effort. Terry and Bukka have never acted before.

"I'm really nervous," says Terry.

"I'm not really nervous," says Bale.

"Wait 'til the proper time comes. Your stomach goes through your throat," Jo Harvey tells him with an easy Texas drawl.

She has been on some sort of stage or another for seven years. Her acting debut came in Terry's video, "The Embrace . . . Advance to Fury," that won an American Visual Arts Award. Reynolds also appeared in the video. It was shown at the National Gallery in 1982 along with other Visual Arts Award winners and at the Hirshhorn last October.

Jo Harvey, 42, has performed her own plays in cities across the country, received two National Endowment for the Arts artist fellowships and published three books. She just completed a two-month, 10-city tour with a stand-up revue, "As It Is in Texas."

Terry, also 42, has exhibited his drawings, paintings, sculptures and videos nationwide. His plays have been performed in California, and he has made three records with The Panhandle Mystery Band, in which he plays piano and composes. He also taught art for seven years at California State University at Fresno, a position he resigned in 1979 to devote more time to his own projects.

Life for the Allens sounds a bit like living theater. After rehearsals they stay up and talk. "We talk about when we were the kids' age," says Terry. "We did crazy things. But now when they act crazy, we jump on them , when they're driving too fast, staying out too late . . . You kind of see yourself being a hypocrite. Maybe that's what you have to be when you're a father. A real slick hypocrite."

The family came here on June 18 with a first draft of the play, which they've since scrapped. Since then they've written three versions, working as a committee. "We really tried to do it in a democratic way," says Jo Harvey. "We made sure that everyone got their way enough that they felt happy about it."

"It's not a linear story," says Terry. "I don't know how we could do a traditional narrative."

"We're all too nuts," says Jo Harvey, laughing.

"It takes place in parts of the mind," says Terry.

"But it centers around the dining-room table," Jo Harvey adds.

Jo Harvey and Terry met when they were children in Lubbock, Tex. Terry's father, Sled Allen, was a baseball player in the Texas League and with the old St. Louis Browns. When he retired from pro ball, he opened an entertainment hall that featured wrestling, boxing, blues and rock 'n' roll. Terry's mother was a ragtime piano player. Jo Harvey's mother sold dresses in a clothing store and her father was a carpenter.

They married there in 1961, with $15 wedding rings they bought in a supermarket, moved to Los Angeles, had two children, moved back to Texas briefly, went to Berkeley, Calif., when Terry became a visiting artist, and moved permanently to Fresno in 1971 for his teaching job. Their son Bukka is now 18 and Bale is 17.

Later on they got remarried "our way" and had tornadoes tattooed onto their left ring fingers. At the base of the tornado are four dots, representing the four Allens.

"We think of ourselves as close but really separate. Four rocks," says Jo Harvey.

Individuality is prized. Terry says that many people are "trying in general to become as much alike as possible. You go to Thailand and there's a Pizza Hut. That's tragic because so many cultures are being lost." He spent six weeks in Thailand recently working on the music for a German documentary about Amerasians living there.

Terry says the family is pretty stable. "We've fought like cats and dogs, but that's the way we salvage things."

The house in Fresno, Jo Harvey says, is hectic: "Someone made a comment that they liked our house because every room is like a kid's room. We don't have a whole lot of furniture but we have lots of records, books, drawings on the walls, and kids are always there. We really like that."

They say they love to go to small cafe's just to watch people. "We go to a coffee shop at least three times a day," says Terry. When Jo Harvey and Terry were coming home from the hospital after Bukka was born, they stopped off at a coffee shop for a couple of hours.

"I work in coffee shops," says Jo Harvey. "I go and rehearse. It is so quiet in a coffee shop compared to our house."