TONIGHT'S MUST-SEE

Basketball, 3 p.m., CBS. This is the big one, for the college championship. Even before Saturday's games, fans knew it would be a good one. All of the tournament's top-seeded teams — Kansas, Memphis, North Carolina and UCLA — reached the final four.

"Medium," 9 p.m., NBC. The two talented Arquette sisters had never really acted together before. You could blame that on their age gap (Rosanna is nine years older than Patricia) or sheer circumstance; now it's resolved. Allison (Patricia) probes a possibility: A woman (Rosanna) may be dating and then killing younger guys.

OF NOTE

"America's Port," 4 and 7 p.m., National Geographic Channel. Almost half the nation's imports arrive at the Los Angeles port or the neighboring one in Long Beach, this fairly interesting documentary series says. Now, as the show settles into its regular night, we see a search for drugs and a body. We also catch the calm interplay between a veteran captain and his son, fresh from the California Maritime Academy.

"Big Bang Theory" and "Two and a Half Men," 7 and 7:30 p.m., CBS. These two comedies will follow the game in some time zones, so CBS is tossing in reruns. First, Sheldon is fired; then Alan's girlfriend (Janeane Garofalo) behaves oddly after sex

"Dancing With the Stars," 7 p.m., ABC. Last week Steve Guttenberg was ousted. Tonight, the nine survivors try a Viennese waltz or paso doble.

"High School Confidential," 7 and 10 p.m., WE. What's it like to be transplanted from Thailand to Kansas? This four-year documentary traces Crystle, a Thai beauty who thrives at modeling and stumbles over friendship. It's well-made; so is the 6 and 9 p.m. rerun, which follows three high-achievers.

"House," 7 p.m., Fox. New episodes are still three weeks away. In this rerun, a 600-pound man comes out of a coma.

"New Amsterdam," 8 p.m., Fox. John's previous police partner had a dying request. That triggers some reflection by John, who won't be giving any dying thoughts; he's been alive for about 400 years.

"Samantha Who," 8:32 p.m., ABC. After a long break, this comedy returns. Samantha has amnesia, but lease problems require her to move back in with her former boyfriend Todd.