TONIGHT'S MUST-SEE

"Wedding Bells," 8 p.m., Fox. On a night that's often humorless, this series — about three sisters running a wedding business — offers fresh fun. It has switched episodes for tonight, inserting a broadly funny hour. Everyone — except the bride and groom — is convinced the groom is gay. The bride's dad (Dan Lauria of "Wonder Years") is so sure that he refuses to pay for the wedding. It's a funny hour but brings an oddity: In the original plan, the older sister (Teri Polo) was the dependable one; now that has somehow shifted to the middle sister (KaDee Strickland). It may take a while for "Bells" to find itself.

Basketball, 6 a.m. and 1 p.m., CBS. Here are two more doubleheaders in the NCAA tournament with the games varying by region. By the end of the night, the field will be down to 32.

OF NOTE

"An Inconvenient Truth," 3:45 p.m. Showtime. Here's another chance to catch this film, shortly after it won Academy Awards for best documentary and best song. Al Gore offers a lecture on global warning.

"Grey's Anatomy" (ABC) and "House" (Fox), each 7 p.m. Colliding are reruns from two of TV's best shows — both set in sophisticated hospitals with cranky doctors. ABC repeats the Thursday hour, in which the competition for chief of surgery gets crowded. Fox repeats an earlier episode in which a man is hospitalized after fighting with Dr. House.

"1 vs 100," 7 p.m., NBC. There might be a '50s feel to the "mob" facing the contestants tonight. It includes members of Sha Na Na plus actors Jeff Conaway and Susan Buckner who were Kenickie and Patty Simcox in the "Grease" movie. Also appearing are former "Apprentice" contestants Kelly Perdew and Omarosa Manigault-Stallworth.

"Identity," 8 p.m., NBC. This game show — which was only so-so in ratings and quality during its December tryout — is back for another round. Penn Jillette hosts.

"Law & Order," 9 p.m., NBC. Tonight's target is the "Girls Gone Wild" people. This show envisions a seedy operation called "Babes Being Bad." When one of the guys is murdered, there are plenty of suspects.