Some D.C teen-agers hired by the city government spent their summer working in offices as file clerks and receptionists, but a group of 13 others worked in summer stock, painting scenery, making costumes and successfully performing a popular play last weekend.

For four consecutive nights the troupe appeared in Joseph Kessering's "Arsenic and Old Lace" at the Market 5 Gallery in the Eastern Market, the finale to their summer jobs.

Members of the troupe, called Young Players of Capitol Hill, were among 600 District youths who were paid by the Mayor's Summer Youth Employment Program to work in acting, dance and music programs during the summer under a project sponsored by the D.C. Commission on the Arts and Humanities.

Two months of hard work preceded the group's moment in the footlights. Director Deirdre Cohalan, 17, and assistant director Jon Blum, 18, organized the troupe in the early spring after holding auditions. As spring became summer the troupe formed prop, costume, performance and public relations committees.

"We put in eight hours a day," said Blum. "But that's just part of it. We are fortunate to be acting and getting paid. The best part about being here is that you work together to produce something. Most people have jobs at Roy Rogers. They punch in, they punch out. They make french fries."

In June and July the group searched for costumes and for inexpensive construction materials for the sets.

Between the hammering, nailing and painting of the scenery, they rehearsed for their skits from "Aesop's Fables," which they performed at the Eastern Market on Saturdays.

They baked and sold cakes and pies and hawked T-shirts, and by last week had raised $150 to pay their expenses.

"Everybody really does everything," said Cohalan. "So much faith and responsibility has been given to us. It inspired me, because I've been given a lot of responsibility--it's good for me."

The youths, aged 14 to 21, earned the minimum wage of $3.35 an hour for working five hours a day, five days a week, from city funds provided to Arts D.C., an umbrella organization of about 60 city arts groups sponsored by the D.C. arts commission.

John Harrod, executive director of the Market 5 Gallery, an art gallery that offers live performances, said he asked for the Young Players troupe. "We are able to hire an excellent mixture of young people from varied economic, cultural and social backgrounds," said Harrod. "They have to share with each other. They do a lot on their own, too. I'm very happy with them."

The cast members are similarly satisfied. "The unity that comes from this summer is great," said Blum. "It's like a big family. Everyone who comes in here is immediately accepted."

For some members of the acting troupe, the summer provided valuable experience for the careers they want in television or theater. For others, it was simply fun.

Piper Dellums, who will attend the University of California at Berkeley in September, wants to become a child psychiatrist but has performed in various Walt Disney Productions. This summer she played the part of a throaty-voiced, wild-eyed female Dr. Einstein, a role usually given to a man. "I like challenging theories," said Dellums, daughter of Rep. Ronald Dellums (D-Calif.), adding that she also likes the variety of concepts in chemistry and biology.

Blum, who played three roles in the production of "Arsenic and Old Lace" in addition to his job as assistant director, will enter Emerson College in Boston next month.

He said he always thought he wanted a glamorous career on the stage. But at the group's last bake sale, as he stood beside trays of chocolate chip cookies and brownies melting in the midday sun, Blum laughed and said,"I don't know if I want to be an actor."