TONIGHT'S MUST-SEE

"Heroes," 8 p.m., NBC. Plenty of characters are unhappy about their special abilities. Now we meet Elle, who's the opposite. "She very much enjoys her power," said Kristin Bell, who plays her. "And enjoys the power it gives her over people." Bell won't specify, but this clearly isn't a pleasant power. "She's so messed up," she said. She has reason to be, said creator Tim Kring. Lately, we've heard about the company that has manipulated things; it turns out that Elle grew up within it. Now she's searching for Peter, Bell said. "She knows a lot about Peter's past."

"MonsterFest," AMC. Horror films, everywhere. This is the start of the 10-day TV fest stuffed with movies. Tonight, that includes Wes Craven's dandy "Scream 3" (2000) at 5 p.m. There's plenty of competition. At 7:30, ABC Family has "Poltergeist" (1982), superbly directed by Tobe Hooper and produced by Steven Spielberg. At 8, the Disney Channel has the milder "Twitches Too" (2007).

OF NOTE

"Chuck," 7 p.m., NBC. Chuck is just starting to learn his spy skills and now he might have to work alone. He wants to help a Chinese agent, but the CIA isn't interested.

"Celebrity Expose," 7 and 8 p.m., MyNetwork TV (KFVE). A new portrait of Brad Pitt and Angelina Jolie is followed by the rerun of a Lindsay Lohan profile.

"How I Met Your Mother," 7 p.m., CBS. Ted has a new girlfriend, and a problem: Barney already considers her crazy.

"The Big Bang Theory," 7:30 p.m., CBS. Sara Gilbert guests. She plays a fellow scientist who has a one-night stand with Leonard.

"Two and a Half Men," 8 p.m., CBS. Charlie is still with Linda (Ming-Na Wen), the age-appropriate judge. His new challenge is baby-sitting for her 4-year-old.

"Samantha Who?" 8:30 p.m., ABC. In last week's delightful opener, Samantha (Christina Applegate) woke from a coma; she began to learn that her family and friends are shallow and self-centered — and so is she. Now she returns to work, where she learns more about her bad behavior.

"Journeyman," 9 p.m., NBC. Dan goes back in time tracking a former Army Ranger who stole money for a cause.

"The Mysterious Human Heart: Silent Killer," 9:30 p.m., PBS. The documentary series concludes with this look at atherosclerosis, which blocks the arteries.