THURSDAY

Masterpiece Theatre "Upstairs, Downstairs", this year's hot BBC serial, begins an encore 13-week run tonight. Alistair Cooke is host. Ch. 2, 9 p.m. 1 hour.

The Big Shot (1942). Humphrey Bogart is a gangster on the lam in a flashback from his deathbed. Ch. 56, 11:30 p.m. B/W, 2 hours.

FRIDAY

Ben Hur(1959). The latest in a recent spate of huge, gigantic, incredible spectacle films on TV. This won more Oscars than any movie in history (11), but it's still a good film. (Especially the chariot race scenes.) Ch. 7, 8 p.m. Color, 3 1/4 hours.

SATURDAY

Much Ado About Nothing. The highly-acclaimed Joseph Papp adaptation of Shakespeare, set in World War I America. Ch. 2, 7 p.m. 3 hours.

SUNDAY

The Incredible Mr. Limpet (1964). Don Knotts is a wishy-washy bookkeeper who becomes a fish. This sounds dumb, but it isn't half bad. The animated scenes of Knotts as the fish are better than Disney, and the plot (the Navy tries to use him to bomb enemy subs but he has cold fins about it) is pretty daring for a kid's film. Ch. 56, 12 noon. Color, 2 hours.

Thursday's Game (1974). A made-for-TV movie, but it sounds good. (Anything with Gene Wilder, Rob Reiner, Valerie Harper and Bob Newhart couldn't be all bad.) This is about a game show producer who gets depressed, or something like that. Ch. 5, 8:30 p.m. Color, 2 hours.

The First Woman President. The fascinating story of Mrs. Woodrow Wilson and how she ran the government after her husband became paralyzed. With Eva Marie Saint. Ch. 7, 9:30 p.m. 1 hour.

NBC News Presents. "You're Too Fat," an examination of lard in America. Ch. 4, 10 p.m. 1 hour.

TUESDAY

God is My Co-Pilot (1945). A war movie worth listing just for the title. CH. 56, 12:30 p.m. B/W, 2 hours.

The Last Angry Man (1974). A cranky but eminently decent Brooklyn doctor refuses to let a TV crew glorify his life it the filming means interrupting his work. CH. 5, 8:30 p.m. 1 1/2 hours.