NCIS (7 p.m., Ch. 2): Tony and Ziva go undercover as married assassins to infiltrate a terrorist cell.
Nova (7 p.m., Ch. 7): In "Hitler's Sunken Secret," divers search a sunken Nazi ship to find evidence of just how close the Germans were to developing atomic weapons.
Gilmore Girls (7 p.m., Ch. 30): Rory's ex-boyfriend, Jess (Milo Ventimiglia), shows up with some amazing news. And Jess doesn't get along with Rory's new boyfriend, Logan.
Amazing Race: Family Edition (8 p.m., Ch. 2): One of the contestants gets in trouble in the water in this two-hour edition.
Commander in Chief (8 p.m., Ch. 4): A tell-all book about the president leads to a search for the leak inside the White House.
My Name is Earl (8 p.m., Ch. 5): Earl atones for stolen beer and a golf obsession.
House (8 p.m., Ch. 13): Lies told by both a patient and his father hinder House from diagnosing the problem.
All-Star Salute to Patti LaBelle (8 p.m., Ch. 24): LaBelle is joined by Ashanti, Big Boi, Boyz II Men, Gerald Levert, Mario, Michael McDonald, Nelly and Kelly Rowland.
Supernatural (8 p.m., Ch. 30): There's a lesson to be learned in this episode — if you build housing on an ancient Indian burial ground, bugs are going to eat your brain.
Boston Legal (9 p.m., Ch. 4): This show has been a lot of fun this season, deftly mixing over-the-top comedy with drama and pathos, but tonight's episode is a sign executive producer David E. Kelley and his team may already be pushing this into bad "Ally McBeal" territory. Alan's fear of clowns is sort of stupid; Denny's behavior toward a client is outlandish and unbelievable; but the plotline about the guy who cheats on his wife with a cow is just distasteful.
Law & Order: SVU (9 p.m., Ch. 5): The discovery of a boy's remains 30 years after he disappeared sets off a search for five other missing boys.
Frontline (9 p.m., Ch. 7): A report on the pro-life strategy of driving doctors and clinics away from performing abortions.