Tim Conway returns to primetime in the half-scripted, half-improvisational series “On the Spot” (8:30 p.m., WB). Other familiar faces on “Spot” include Chip Esten and Jeff B. Davis from ABC’s “Whose Line is it Anyway?”

Conway stars in tonight’s debut episode as a businessman looking for a new manager for his run-down hotel. Still one of the great improvisers, Conway offers a dead-on imitation of a phone call breaking up into static.

Periodically during the action, the emcee will ask members of the studio audience to offer suggestions about the next plot point. While this should make for hilarity, it serves to slow the story down to a crawl. The British and American versions of “Whose Line” did this much better, without asking viewers to sit through a half-hour improvised story.

“Spot” also suffers from a distinct lack of original material. The talented Michael Hitchcock (“Best in Show”) and Mindy Sterling (“Austin Powers”) are wasted here as super-square lounge singers who perform hip-hop and other contemporary numbers.

If this sounds familiar, it’s because Will Ferrell and Ana Gasteyer did it for several years on “Saturday Night Live.”

“Spot” is a curious concoction for the WB weblet. Many of its youthful viewers were not even born when “The Carol Burnett Show,” home to some of Conway’s great comedy routines, went off the air in 1979.

One of the most recognizable faces in TV comedy history, Conway’s credits include the 1963-66 combat comedy “McHale’s Navy” and his stint as a regular on “The Steve Allen Show.”

Tonight’s other highlights

Primetime NCAA Basketball Tournament games (6 p.m., CBS) begin. “March Madness” will conclude April 7 with the NCAA title game in New Orleans.

Special Forces capture an al-Qaida nest on “Profiles from the Front Line” (7 p.m., ABC).

Eight finalists are judged on the series finale of “Are You Hot: The Search for America’s Sexiest People” (7 p.m., ABC).

The “Daily Show’s” movie critic makes his Oscar picks known on “Frank DeCaro Big O Special” (8 p.m., Comedy Central).

A deadly virus traps some staff in a quarantined hospital on the repeat season premiere of on “ER” (9 p.m., NBC).

Cult choice

A crooked prizefighter (Marlon Brando) questions his role in the rackets in director Elia Kazan’s 1954 drama “On the Waterfront” (7 p.m., AMC).

Series notes

Christmas in Tulsa on “Friends” (7 p.m., NBC) … Wrestling on “WWE Smackdown” (7 p.m., UPN) … The “L” word on “Sabrina the Teenage Witch” (7 p.m., WB).

Rick Schroder guest stars on “Scrubs” (7:30 p.m., NBC) … Uncle Bill’s gang doesn’t bond with his girlfriend’s brood on “Family Affair” (7:30 p.m., WB).

An impromptu wedding in the park on “Will & Grace” (8 p.m., NBC) … Improvisation on “Jamie Kennedy Experiment” (8 p.m., WB) … Gavin and his agent (Fran Drescher) play hard ball with Jake on “Good Morning, Miami” (8:30 p.m., NBC).

Late night

Jay Leno welcomes Drew Barrymore, Adrien Brody and Nelly on “The Tonight Show” (10:35 p.m., NBC) … Queen Latifah, Colin Quinn and Lou Reed appear on “Late Show with David Letterman” (10:35 p.m., CBS)

Robin Williams and The Other Ones appear on “Late Night with Conan O’Brien” (11:35 p.m., NBC) … Susan Sarandon, Anthony Anderson and Slobberbone are booked on “The Late, Late Show with Craig Kilborn” (11:37 a.m., CBS).