TONIGHT'S MUST-SEE

"Fat March" season finale, 8 p.m., ABC. This all started with a dozen overweight people — ranging from 225 and 234 pounds to 470 and 500 — in Boston. Tonight, the survivors wrap up the 570-mile walk to Washington, D.C. They split a potential $1.2 million pool.

OF NOTE

Football, 1 p.m., ESPN. "Monday Night Football" begins with a rare doubleheader. The first game has Baltimore at Cincinnati. The second, at about 4:15 p.m., has St. Louis at San Francisco.

"The Closer," 5 and 6 p.m., TNT. This two-parter wraps up the season for a terrific show. First is a rerun of last week's hour, centering on the murder of a big-money divorce lawyer. Then comes a new hour: The suspect has a solid alibi; Brenda considers the possibility that she accused the wrong person.

"Prison Break," 7 and 8 p.m., Fox. Sara faces trial in Chicago, in these two reruns. Meanwhile, forces converge in Panama — including Mahone, ready for a re-arrest.

"How I Met Your Mother," 7 p.m., CBS. Here's a rerun of the wedding for Marshall and Lily. Naturally, it falls apart in funny ways; surprisingly, Barney straightens it out.

"My Boys," 7 and 7:30 p.m., TBS. First, P.J. brings her studious new boyfriend (Michael Landes) to poker night. Then comes the season finale: It's time for the trip to Italy, but she still hasn't found the right guy to take. We found the ending to be too cute and frustrating; still, "My Boys" remains an easy, breezy pleasure.

"Heroes," 8 p.m., NBC. This episode introduced Missy Peregrym as the shape-shifting Candice Wilmer. (Peregrym has done some "Heroes" work for the upcoming season, even though she's co-starring in the CW's dandy "Reaper.") Also, Nathan meets Linderman.

"Two and a Half Men," 8 p.m., CBS. Enrique Iglesias plays the handyman who steals Charlie's latest love.