Community theater in Northern Virginia is going with the old stand-bys this October, shows we know so well that we can almost mouth the words.

Theatergoers can look for works such as Frank Loesser's "Guys and Dolls" (The Blue Ridge Alliance of Performing Arts, Sterling, Oct. 9-10, 16-17, 24-25. Phone 430-9228); "Murder on the Nile" by Agatha Christie (Falls Church Players, Oct. 16-17, 23-24, 30-31. Phone 534-7716), and Richard Rodgers' and Oscar Hammerstein's "South Pacific" (Fauquier Community Theatre, Warrenton, Oct. 16-17. Phone 703-349-8760).

Still, one never knows what to expect as the month of theater starts out. It's highly likely a company will turn in a performance to make some of these old jewels shine again.

There are also some more complicated and potentially challenging plays for this month. Four are darker and more depressing than typical fare, but well worth a look.

The Port City Playhouse in Alexandria will perform "Ladies in Retirement," a psychological melodrama about two sisters caught up in a web of murder (Oct. 16-17, 23-25 and 30-31. Phone 838-9303).

The Friendship Players in Falls Church will open its season on Oct. 23 with Frederick Knott's "Wait Until Dark," the tale of a blind woman terrorized by drug dealers who want a heroin-filled doll, unknowingly carried by the woman's husband (Oct. 23-24, 30-31, and Nov. 6-7. Phone 256-6840).

The Saints and Cynics of Saint Dunstan's will perform John Patrick's "The Hasty Heart." The story, about six men of different nationalities in a Southeast Asian British army field hospital during World War II, shows the compassion that can exist in wartime (Oct. 31, Nov. 6-7, 13-14. Phone 759-6924).

That somber tone is also evident in the Little Theatre of Alexandria's presentation of "Look Homeward, Angel," a Pulitzer Prize-winning drama based on the Thomas Wolfe novel. The story chronicles the coming of age of W.O. Gant's children in the South at the turn of the century, and it's full of the black, bottom-of-the-soul humor that turns too quickly to raw reality. (Oct. 30-Nov. 21. Phone 683-0496).

Other plays are mostly lighter fare. They include Mitch Leigh's "Man of La Mancha" (Springfield Community Center, Oct. 9-10, 16-18, 23-25, 30-31. Phone 321-7229); Neil Simon's "Odd Couple" (McLean Center Theatre, Oct. 16-17, 23-25, 30-31. Phone 323-6839); and David Shire's "Starting Here, Starting Now" (Great Falls Players, Oct. 23-24, 30-31, Nov. 6-7. Phone 391-1275).