TONIGHT'S MUST-SEE

"Chuck," 7 p.m., NBC. This series has been great fun but leaves a question: Chuck is intelligent and likable, but unfocused. Burrowed in a big store's "Nerd Herd," he's done little to find money, romance or happiness. What happened to his ambition? We start to find out tonight in the first of several episodes with Jordana Brewster, the beauty from "As the World Turns," "The '60s" and "The Fast and the Furious." She plays his former girlfriend Jill. When Chuck meets her on a repair job, he tries to feign success. Then he spots a secret that brings in colleagues from his secret spy duties.

TONIGHT'S MIGHT-SEE

"Spider-Man 2," 2004, FX, 6 p.m. "Spider-Man 2" is, like the original, a high-octane adventure with human moments.

OF NOTE

"The Wedding Singer" (1998), 7 and 9 p.m., ABC Family. This is a romantic comedy starring Adam Sandler and Drew Barrymore.

"Big Bang Theory," 7 p.m., CBS. Sheldon remains one of the best characters on TV, but lately this show has overused and exaggerated him. Tonight he bans Penny from the apartment he shares with Leonard.

"How I Met your Mother," 7:30 p.m., CBS. Lily considers having a baby.

"Heroes," 8 p.m., NBC. What caused ordinary people to turn profoundly evil? To learn about this, Hiro must go into the past and follow Arthur Petrelli when he created Pinehearst.

"Two and a Half Men," 8 p.m., CBS. Things are complicated now that Judith and Herb have split. He's chasing women with Charlie; she's too needy with her exhusband Alan.