Television returns to its mid-century roots with a biography of the medium’s favorite comedienne, a reunion of America’s favorite sitcom couple and a splendid reworking of a decadent drama from Tennessee Williams.

• We’ve had our share of warts-and-all dramas about showbiz legends this season. We’ve seen Jackie Gleason the philandering drunk and the uneasy union of the needy Jerry Lewis and the distant Dean Martin. So why should “Lucy” (7 p.m. Sunday, CBS) be any different? Within moments of the credits, Lucille Ball (Rachel York) and her estranged husband and business partner Desi Arnaz (Danny Pino) are hurling insults and obscenities at each other on their way to perform the very last episode of their show before a live studio audience.

The rest of this three-hour movie unfolds in a series of flashbacks leading us up to this unhappy denouement. We flash all the way back to young Lucy’s (Madeline Zima) flirtation with rebellious flapperhood during in the roaring ’20s. She later meets an imperious young Bette Davis (Priscilla Bonnet), and claws her way from chorus girl to cigarette girl to the RKO stable of B-movie stars. There she befriends A-list comedienne Carole Lombard (Vanessa Gray) and her beau Clark Cable (Charles Unwin), and runs into a rising young Cuban actor, singer, bongo player and on- and off-screen Latin lover named Arnaz.

“Lucy” is at its best before Lucille Ball becomes TV’s Lucy, and at its weakest when York has to reenact the classic comedy routines we all know so well.

• Olivier Martinez, the French actor who played Diane Lane’s adulterous lover in “Unfaithful,” returns to steamy form as a decadent gigolo in the new adaptation of the Tennessee Williams story “The Roman Spring of Mrs. Stone” (7 p.m. Sunday, Showtime). Helen Mirren dominates the film in the title role. A recently widowed actress, Stone feels adrift in the ancient Italian city until a fallen contessa (Anne Bancroft) introduces her to a series of pretty young men, who all seem to have desperate relatives in need of large sums of cash.

But after a chaste marriage to the impotent Mr. Stone (Brian Dennehy, seen briefly at the start), Mrs. Stone begins to enjoy and then crave the pleasures of the flesh, particularly those of the young Paolo (Martinez).

“Spring” is the kind of smart, sexy movie that Hollywood just doesn’t release in theaters anymore. Don’t miss it.

Today’s highlights

• Russell Crowe stars in the 2001 epic “Gladiator” (7 p.m., ABC). Note: Some affiliates may opt instead to air a debate between Democratic presidential candidates.
• Stephen Baldwin stars in the 2003 made-for-TV crop-circle thriller “Silent Warnings” (8 p.m., Sci Fi).
• Ashton Kutcher is host of “Saturday Night Live” (10:30 p.m., NBC), featuring musical guest 50 Cent.

Sunday’s highlights

• The Kinks (Third Eye Blind) perform on the Jersey Shore on “American Dreams” (7 p.m., NBC).
• Dick Van Dyke and Mary Tyler Moore reunite to star the TV adaptation of D.L. Coburn’s stage drama “The Gin Game” (8 p.m., PBS, check local listings).
• Sydney just can’t trust Mom on the two-hour season finale of “Alias” (8 p.m., ABC).
• “Dark Roots: The Unauthorized Anna Nicole” (9 p.m., Showtime) takes a condescending look at the chesty exhibitionist’s Texas roots.