TONIGHT'S MUST-SEE

"24," 7 and 8 p.m., Fox. Back-to-back episodes give us "24" at its best, high-stakes and high-octane. Last week, the president gave in to terrorists' demands. He didn't stop an attack on a motorcade that included his own wife and the Russian leaders. They survived and his wife (Jean Smart) is fuming. Frustrated, the terrorists are carrying out their threat to release nerve gas. Tonight's first hour has fierce scenes in a hospital. Both hours have seething moments as Jack Bauer confronts a nerve-gas manufacturer and his wife (Peter Weller and JoBeth Williams). The second hour slows down long enough for personal moments. Kim Bauer is back, and she still thinks her dad is dead. Tony Almeida is awake, and he still thinks his wife is alive. Stick around, however, because there are big moments late in the hour. One — with a window separating two friends — is powerful.

OF NOTE

"History of the Chopper," 6 p.m., Discovery Channel. This history of motorcycles is told by Jesse James, who customizes choppers, hosts "Monster Garage," is married to Sandra Bullock and is a distant relative of the outlaw of the same name.

"How I Met Your Mother," 7:30 p.m., CBS. It's decision time for Ted because Victoria (Ashley Williams) might go overseas.

"Two and a Half Men," 8 p.m., CBS. Alan is reluctant to have his young girlfriend come to his son's birthday party.

"Supernanny" return, 8 p.m., ABC. Stepping back into the lineup, this show starts with a huge challenge: A single mom is returning to school and has five children ages 4-7, including two sets of twin boys.

"The Apprentice," 8 p.m., NBC. One team loses big, igniting an angry boardroom scene. Emotions are stirred among contestants — and probably among viewers. One person seems to have exaggerated a confrontation. There are perceptive moments here by Donald Trump and his observers — Ivanka Trump (his daughter) and Bill Rancic (the show's first winner).

"Beautiful People" return, 9 p.m., ABC Family. This drama is back for the second half of its season, promptly linking two "Melrose Place" actors. Daphne Zuniga stars as an aspiring designer who moved to New York with her teen daughters. Grant Show plays her ex-husband, battling for custody of the younger one, Sophie.

"Miracle Workers" debut, 9 p.m., ABC. Two stories are juggled — both using new technology to face old problems. One involves a woman, 47, who is virtually paralyzed by back pain. The other involves a man, 34, who has been blind since 12. He's never seen his wife and their three kids. His story brings strong waves of emotion.