TONIGHT'S MUST-SEE

"How I Met Your Mother," 7 p.m., CBS. These friends try one of the most difficult feats in our connected society — going all day without learning who won the Super Bowl. There are good (and funny) reasons for this, as well as hurdles. Barney has bet a bundle on the game, Ted must enter a sports bar, and Robin anchors a newscast. There are wonderful moments here, including a great bit with Emmett Smith. Often overlooked "Mother" may be near "The Class" as TV's cleverest comedy.

"Rules of Engagement" debut, 8:30 p.m., CBS. This new comedy seems fresh and funny and a bit too familiar. By coincidence it's a lot like Fox's " 'Til Death" — with an optimistic young couple and a skeptical older one. The difference is that CBS injects a fifth party (David Spade), single guy who is wildly cynical. For all its familiarity, "Rules" remains fun. We root for the young couple (Oliver Hudson and Bianca Kajlich), while taking guilty pleasure at every cynical shot that is fired their way.

OF NOTE

"Lincoln Heights," 7 p.m., ABC Family. Jason Gedrick plays Eddie's old high school classmate now botching a bank robbery.

"Prison Break," 7 p.m., Fox. The brothers remain intent on proving Linc innocent. Tonight, they daringly head toward Chicago with Kellerman and Sara.

"Montana Sky," 7 p.m., Lifetime. After a strong start last week, Lifetime's series of four Nora Roberts films slips in quality. This story is like a sludgy mixture of "King Lear," cowboy films and a Paris-and-Nicole tale. A mogul wills his ranch to his three daughters but only if they live there for a year. Only one (Ashley Williams) is a real cowgirl. One is timid and another is Hollywood fluff.

"Two and a Half Men," 8 p.m., CBS. Charlie sets up Alan with a hot new neighbor.

"Heroes," 8 p.m., NBC. Hiro tries to convince his father (George Takei of "Star Trek") and sister that his mission makes sense.

"24," 8 p.m., Fox. In the aftermath of the nuclear explosion, Jack has tenuously bonded with his dad (James Cromwell) while Lennox, the chief of staff, pushes his aggressive plan with the president.

"American Experience: The Living Weapon," 9 p.m., PBS. This documentary profiles the biological-weapons program that the U.S. maintained from 1942 to 1969.

"Studio 60 on the Sunset Strip," 9 p.m., NBC. As this two-parter wraps up, Danny and Jordan remain locked on the roof while Harriet's party crumbles.

"In Style Celebrity Weddings," 9 p.m., ABC. This special leaps between highlights of people who are talented (Avril Lavigne) or famous (Tori Spelling) or both (Tom Cruise). Some of them - especially Marcia Cross — have interesting comments; the narration, however, is pure drivel.