Happy Days, Samuel Beckett's two act, two character play about desolation and an enduring human spirit, begins its first weekend of performances tonight at the Loeb. This is the Summer Repertory Theater's last production of the season, and its most difficult one. Sustaining an actionless duologue is no simple feat, but the play manages to carry it off. Joanne Hamlin, who delivers most of the lines in the show, gives a fine performance under difficult circumstances. Still, the play and the production are not too satisfying. Geoff Garin's review appears on page two of this issue. Tickets for the weekend cost $5.95. Tonight's show begins at 8, tomorrow the curtain goes up at 5 and 9.

The Drunkard is a very old musical play about alcohol and the wages of sin, and it's being produced at the 369 School for the Performing Arts up in Somerville. The play was written in the 1840s, but apparently got changed by bits and pieces over the years. With some excellent background work, the people at 369 have gone a long way to restoring the piece to its original condition. The music for the play is lost, but the show's producers have come up with a score that is purportedly true to its source. Weekend performances begin at 8, tickets are $3.

Antigone has gone through still another rewrite, this one by Steven Lydenberg, and is being presented this weekend in Inman Sq. at the People's Theater. Shows begin at 8:30.

Moon Children, by Michael Weller, continues its run at the Charles Playhouse. This is really fine: funny, sad, and as accurate a portrayal of student life as you're likely to see on the stage. The play is about the people Weller shared a house with during his senior year at Brandeis. If you already know what student life is like, but don't object to good comedies, you'll enjoy it anyway. The Playhouse is located at 76 Warrenton St. in Boston. Friday shows at 7 and 10:30, Saturday at 6:30 and 10, Sunday at 7:30. Student tickets cost $3 at Friday's late performance.

Jacques Brel is Alive and Well and Living in Paris, but how would he be doing if he had to live in Cambridge during the summer? Anyhow, this is purportedly Boston's longest-running musical, and a pleasant enough way to spend an evening.