The sprightly 1990 Back to the Future,...

The sprightly 1990 Back to the Future, Part III (NBC Sunday at 8:30 p.m.) satisfyingly ties up the various plot strands that were left hanging from “Part II” of the time travel trilogy. This time, director Robert Zemeckis and writer Robert Gale indulge their love of Westerns. Through a series of blissfully nutty schemes, Marty McFly (Michael J. Fox) travels back to the Old West, circa 1885, to try to rescue Doc Brown (Christopher Lloyd) before he’s shot in the back.

The uneven 1989 Courage Mountain (KTLA Monday at 8 p.m.) is but “The Further Adventures of Heidi”--moved up to the outbreak of World War I. Juliette Caton is Johanna Spyri’s Swiss Alpine heroine, now a teen-ager, and Charlie Sheen is unlikely casting as her boyfriend.

George Pal’s 1953 production of H.G. Wells’ The War of the Worlds (KCOP Wednesday at 8 p.m.), a tale of a Martian invasion, is intensely pictorial, consistently imaginative and briskly paced under Byron Haskin’s resourceful direction. Gene Barry, Ann Robinson and Les Tremayne star.

Homeboy (KCOP Thursday at 8 p.m.), a bleak but largely impressive 1988 drama starring Mickey Rourke as an alcoholic boxer, has had only a limited release.

WarGames (KTLA Saturday at 6 p.m.) is a taut, ingenious 1983 winner in which high school computer whiz Matthew Broderick blunders into a game, Global Thermonuclear War, with a Department of Defense computer, which keeps ticking away after Broderick calls its quits.

On a remote Kansas prairie in 1910, mail-order bride Glenn Close and farmer Christopher Walken create a tremulous couple struggling to share a life in the outstanding 1991 TV movie Sarah Plain and Tall (CBS Saturday at 9 p.m.).

KCET is offering a terrific Saturday night double feature with two British classics written by the crack team of Frank Launder and Sidney Gilliat that are arguably the two best mystery films ever set principally aboard a train. The first is Alfred Hitchcock’s 1938 The Lady Vanishes (at 9 p.m.), which finds Margaret Lockwood caught up in a dangerous puzzle once sweet old Dame May Whitty unaccountably disappears; the second is Carol Reed’s 1940 Night Train to Munich (at 10:40 p.m.), a high adventure of the kind paid tribute to by “Raiders of the Lost Ark,” in which Rex Harrison plays a fearless, self-mocking British secret agent, disguised as a Nazi major.