A series of basketball all-star challenges, matching Washington metropolitan area players against teams from Southern Virginia, Baltimore and New York, will tip-off tonight at 8:30 p.m. at McDonough Arena as Washington meets an impressive Southern Virginia team which has five players 6 feet 7 or taller, including 6-9 junior Ed Gett (Norfolk).

Preseason high school all-American Cory Alexander (Oak Hill), 6-7 leaper Jelani Nix (Bladensburg), 6-5 Johnny Rhodes (Dunbar) and 6-5 John Stuckey (Coolidge) will lead the Washington team. Summer Superlatives

Duke-bound Grant Hill is traveling the friendly skies again. Hill, the 1989-90 high school player of the year from South Lakes High, is in Alabama with the U.S. junior national team. The team is headed for a tournament in Uruguay.

Playing without Hill in Jacksonville, Fla., last week, Executive III lost, 125-118, in overtime, to Team Jacksonville in the quarterfinals of the junior men's AAU championships.

Executive III had some impressive performances in defeat. Senior Bill Burnett (Coolidge) was selected to the all-American team. He scored 30 points in the loss to Team Jacksonville. . . .

The finishes of several area summer league games were as hot as the temperature last week.

In the Blair League, DeMatha overcame a 13-point halftime deficit to beat Good Counsel, 61-60. . . .

In the James "Jabbo" Kenner College League at McDonough, James Madison University guard Steve Hood, the Kenner League's Most Valuable Player last summer, scored 57 points Sunday, but they were not enough for DCI to overcome Nike Air, which was an 85-84 winner at the buzzer on Mike Brown's jumper. . . .

The Fairfax League playoffs begin tomorrow with South Lakes as the top seed. Fairfax tested South Lakes last week, but behind Theron Curry's 25 points, the Seahawks hung on to win, 73-72.

Herndon senior forward Luteke Kalombo continues to impress observers. Kalombo scored 26 points in an 86-39 romp over Langley.