Opening this week: Programs for Children and Youth opens its 10th season in the Kennedy Center's Theater Lab on Thursday with "A Family Album," a musical recommended for children in kindergarten through sixth grade. Most performances are for school groups, but there are 27 free public performances during the season of four plays. Call 254-3600 for more details.

Also opening: "Fool for Love" at the Round House tonight, "Othello" at the Folger on Tuesday, "The Good Person of Setzuan" at Arena on Wednesday, "Forbidden Broadway" at the Shoreham on Wednesday.

Arena's opening will signal the start of its 35th season, and the theater is having a gala Thursday to mark the event, with ambassadors from seven countries plus a few cabinet members invited to spark up the evening. Margaret Heckler was invited as secretary of Health and Human Services, but presumably will still be allowed to attend as an ambassador. The diplomats expected to attend include those from both West Germany and East Germany, as well as those from countries in which playwright Bertolt Brecht sought refuge when he fled Hitler's Germany: Switzerland, Denmark, Sweden and Finland.

Coming Attractions: The San Francisco Mime Troupe, still radical after all these years, is visiting Washington Oct. 25 and 26 for three performances of "Steeltown." The group, which is dedicated to political theater with a decidedly leftist view, is not a mime troupe. "Steeltown," in fact, is a musical about working people and unemployment. The group is sponsored by Common Concerns Bookstore, where more information can be obtained (463-6500).

A French troupe called the The'a tre du Graffiti will perform at the French Embassy's theater Oct. 16. The play is "Le Rodeur," about a drifter whose traveling companion is a falcon. Performances are in French with a written synopsis in English available. Call 944 6052.