SATURDAY NBC: Bob Hope Desert Classic Golf (About 4p.m. to finish Sat.; 2:30 p.m. to finish Sunday) Celebrities and pros mix it up.
ARTS (cable): Our Town (9-10:50 p.m.) TV adaptation of Thornton Wilder's classic, starring Sada Thompson and Hal Holbrook.
CBS: Grand Prix Masters Tennis (3-? p.m.)Live from Madison Square Garden.
PBS: Churchill: The Wilderness Years (9-10 p.m.) Second episode of Masterpiece Theater mini-series on Churchill's long, dark 1929-39 decade.
PBS: Frontline (8-9 p.m.) 88 Seconds in Greensboro, a shocking documentary about the murder of five communists allegedly by the KKK and Nazis in Greensboro , N.C.
PBS: Das Rheingold (9-10:30 p.m.) Beginning of Great Performances' Wagner Ring cycle (see the Jan. 19 Arts page).
ALL NETWORKS and CNN: President Reagan's State of the Union message (beginning 9 p.m.)
PBS: Idomeneo (8-11:30 p.m.) Mozart's 1781 opera, with Pavarotti.
Check local listings for all PBS programs.