TONIGHT'S MUST-SEE

"The Class," 7:30 p.m., CBS. Last week's Valentine-themed episode was a delight reminding us how good this show is. Now let's hope viewers discover it in time. Ratings have been borderline and CBS has talked of resting it once it runs out of new episodes. Duncan and Richie have been doing repairs in the massive home of Nicole and her husband. Last week, during a blizzard, she and Duncan admitted they never should have broken up a decade ago. Now she wishes the repairs weren't ending. So, presumably, does Richie, who had a hilarious snow tragedy last week.

OF NOTE

"SpongeBob SquarePants," 3 p.m., Nickelodeon. First we get four reruns of this fun cartoon. That's followed at 7 p.m. by three new episodes, each focusing on Bob's cheery friend, Patrick.

"Carolina Moon," 7 p.m., Lifetime. Here's the last of four new movies based on Nora Roberts novels. The quality has been mixed, but it's worth trying again. Claire Forlani ("Meet Joe Black") plays someone returning to the South Carolina town where her friend Hope was murdered. Many people suspect she's the killer, but Hope's brother has a warmer reaction. He's played by Oliver Hudson. Jacqueline Bisset plays Hope's mother.

"Prison Break," 7 p.m., Fox. After a one-week break, the show is back and in full crisis. In the previous episode, Haywire, cornered, jumped to his apparent death. Michael and Sara barely escaped being caught. Now they're in a Chicago cigar club looking for key information. Meanwhile, Pope (Stacy Keach), the good-hearted ex-warden who feels betrayed by Michael, is back in the picture.

"How I Met Your Mother," 7 p.m., CBS. Ted reluctantly dumps the things given to him by former girlfriends. Then he finds something that gets Robin in trouble.

"Star Trek: Beyond the Final Frontier," 7 p.m., History Channel. Leonard Nimoy hosts this special, which includes interviews with former "Trek" captains Patrick Stewart, Avery Brooks and Kate Mulgrew. It looks at the impact of the shows and interviews some of the directors, designers, writers, prop makers and technicians.

"Two and a Half Men," 8 p.m., CBS. Last week, Charlie gradually realized that Rose really was leaving. (Melanie Lynskey, who plays her, will be in an upcoming Fox series, "Drive.") Tonight, he tries dating a 20-year-old.

"Heroes," 8 p.m., NBC. Claire rages at her father and Hiro has second thoughts about his mission. Matt's world spins out of control as he confronts Ted Sprague and a woman who taps into electronics.

"24," 8 p.m., Fox. Milo and Chloe both find themselves in tough situations.

"Studio 60 on the Sunset Strip," 9 p.m., NBC. Dealing with writer's block, Matt (Matthew Perry) has enough trouble. Now he also meets a lawyer (Kari Matchett of "Invasion") investigating a sexual-harassment claim.