TONIGHT'S MUST-SEE

"Burn Notice," 10 p.m., USA Network. Last week's opener set up the situation beautifully. Michael Weston (Jeffrey Donovan) is a spy, suddenly cut off by the CIA. While trying to learn why, he'll make money from freelance jobs in Miami. Helping are a retired spy (Bruce Campbell) and a former lover (Gabrielle Anwar). Except Michael knows both are reporting back to the CIA. Then there's his hypochondriac mom (Sharon Gless). She has secret information, too; to get it, Michael must help her friend.

"Big Brother 8" debut, 7 p.m., CBS. Back in the summer of 2000, CBS introduced "Survivor" and "Big Brother," starting the reality-show deluge. "Survivor" became a blockbuster, but "Big Brother" — with strangers confined to a house — remains in the summers. This year, it's 7 p.m. Thursdays and Sundays, and 8 p.m. Tuesdays; tonight, Julie Chen introduces the people in the house.

OF NOTE

"Are You Smarter Than a 5th Grader?" 7 and 8 p.m., Fox. Fox had planned to put a movie here. Now, instead, it will rerun two hours of its game show.

"My Name is Earl," 7 p.m., NBC. Joy is happy to know she has a half-sister — until she learns it's her enemy, an aspiring wrestler.

"30 Rock," 7:30 p.m., NBC. Liz finally dumps her boyfriend, the beeper salesman. Now Jenna re-introduces her to the singles scene.

"The Office," 8 p.m., NBC. Ryan, the former intern, is a full-timer now. Alas, Dwight is taking him on a sales call.

"Pirate Master," 8 p.m., CBS. This struggling reality series slides back an hour. Next week, it tries 9 p.m. Tuesdays.

"Grey's Anatomy," 8 p.m., ABC. George and Callie return from Las Vegas as husband and wife. People hardly have time to notice during this crowded rerun. The new clinic is opening, a dangerous disease is rushing through the hospital and Meredith's mom suddenly has her full mental faculties.

"CSI: Crime Scene Investigation," 9 p.m., CBS. This rerun, airing an hour later than usual, has Catherine and a temporary staffer (Liev Schreiber) to track a serial killer.

"ER," 9 p.m., NBC. John Mahoney, the "Frasier" dad, plays a man pushing to keep his gay lover alive, despite indifference from the man's family.

"Men in Trees," 9 p.m., ABC. Marin is sort of settling into this Alaskan town now, even joining the radio show.