* Chuck (8/7c NBC)
After a three-week layoff, Chuck and Sarah returned last week and went full steam ahead to derail some snakes on a train - venomous Spanish spies, that is. Chuck and Sarah's on-and-off relationship is going full throttle as well, but this spiking romance will be tested tonight when they train under the tutelage of Craig and Laura Turner (Fred Willard and Swoosie Kurtz), a married CIA couple with a glowing spy record - but who zestfully despise one another. Are Chuck and Sarah destined for a similarly stormy relationship? And Casey's at the bat in a training mission: He must show the spy ropes to none other than Nerd Herder Morgan.
* House (8/7c Fox)
House is an accomplished-enough musician, so what's he doing in a karaoke bar? Getting rowdy with Chase and Foreman, and lip-synching to Gladys Knight and the Pips, that's what. Takes an edge off the stress. Meanwhile, if you're interested in what's happening with Wilson and Sam, look for developments: Cynthia Watros is back. And back at the hospital, the team's patient not only has a mystery ailment, but he's keeping secrets from his fiancÃÂ©e (Susan Sarandon's daughter, Eva Amurri) as well.
It's back to the Garden State - and a return to jawin' and clawin' mama dramas - when Jersey girls Teresa, Jacqueline, Dina, Danielle and Caroline reassemble for Season 2. The reality soapfest opens its new year with Danielle continuing her efforts to slip into the Jersey-girl inner sanctum. Then there are the Manzo sisters, who develop a tighter bond over the birth of Jacqueline's baby. And Caroline organizes her annual fund-raising event - but she doesn't invite Danielle, who promptly makes everyone aware of the snub.
A heady blend of comedy and drama drives this superb episode, which features an excellent guest-star turn by Barbara Barrie. She plays the irascibly haughty Libby Sussman, a major benefactress of the hospital and a major pain in the neck, who comes to the ER after a dizzy spell and sends everybody reeling. Dr. Cooper, whom she likens to a handsome "action figure," complicates things with one of his inappropriate hands-on moves. At home, some downtime with a disgruntled Kevin blows up in Jackie's face.
* How I Met Your Mother (8/7c CBS)
The complex emotions tied up in the Ted-Robin-Barney love triangle still surfaces in subtle ways, but tonight it leads to a not-so-subtle fight between Ted and Barney, who both claim they love Robin. But it takes a dramatic turn to make Robin realize she's over them. Makes sense. What doesn't is why the most stable and loving of the friends, Marshall and Lily, are getting twin beds!
* Jeopardy! (Syndicated)
The stars come out before nightfall (in most viewing areas) as the 2010 Million Dollar Celebrity Invitational Tournament kicks off the first of three semifinal rounds with Pat Sajak, Jane Curtin and Harry Shearer. Tomorrow's match features Michael McKean, Charles Shaughnessy and Isaac Mizrahi; and Neil Patrick Harris, Jane Kaczmarek and Cheech Marin play on Wednesday. The respective winners then compete in a two-day final round, and the contestant with the highest total earns $1 million for charity.
* NBA Playoff (7/6c TNT)
The Celtics may have the aging core of Kevin Garnett, Paul Pierce and Ray Allen, but it's the ailing right elbow of Cleveland star LeBron James that's getting the most medical scrutiny in this intriguing Eastern Conference semifinal series. Any diminishing of King James' game puts increased pressure on a supporting cast featuring Antawn Jamison, Shaquille O'Neal and Mo Williams, all acquired since the Cavs' seven-game loss to Boston in this round two years ago. Allen was the hottest of Boston's Big 3 in Round 1, connecting on 19 of 36 three-point attempts, most of which were set up by tireless point guard Rajon Rondo.