Traylor Howard and Tony Shalhoub, Monk Traylor Howard and Tony Shalhoub, Monk

9 pm/ET USA
The seventh season wraps up tonight with a case that has special significance to Monk. He's investigating the disappearance of a city official who was lobbying to preserve a parking garage. But what's so personal about that? Well, it's the garage where Monk's wife was killed by a car bomb that he believes was intended for him. The series is scheduled to return for its eighth and final season this summer. —Brie Hearn

Late Night with Conan O'Brien
12:35 am/ET NBC
After 16 years and 2,725 episodes, flame-haired host Conan O'Brien closes the curtain on his consistently entertaining late-night show tonight. Don't expect a Bette Midler tune to send him off à la Johnny Carson's last show — but then again, you never know with Conan's twisty sense of humor. We do know that he's got visceral garage-rock blasters the White Stripes on the slated performance roster. In addition, expect choice comic bits from episodes past (Conan's been doing that all week), plus favorite guests of the show and a surprise or two. Conan's not moanin', however: He returns to NBC on June 1 as the new host of The Tonight Show. —Dean Maurer

10 pm/ET USA
Shawn finds himself in a heap of trouble in tonight's Season 3 finale. The elusive Yin Yang serial killer, who's been off the police's radar for years, suddenly reappears with — of course — his sights set on Shawn. Cybill Shepherd reprises her role as Shawn's mom, Madeline, and Rachael Leigh Cook guest stars as Shawn's high-school crush, Abigail. There's nothing like being hunted by a serial killer to bring the whole crew together, huh? —Brie Hearn

Real Time with Bill Maher
10 pm/ET HBO
Tonight's seventh-season premiere is notable not just for an earlier time slot, but it's the first time the show, which debuted in 2003, will take place with a Democrat in the White House. Of course, that doesn't mean Maher won't have some choice words about Barack Obama's nascent presidency, but there are certainly other fish to fry. Among tonight's guests are Tina Brown, publisher of the website the Daily Beast, and Chrystia Freeland, U.S. managing editor of the Financial Times. —Joe Friedrich

Battlestar Galactica
10 pm/ET SCI FI
Tonight's chapter takes a page from the Clash's songbook as Ellen's return has the skin jobs wondering, "Should I stay or should I go?" With Galactica in need of a major overhaul, the rebel Cylons consider making a fresh start of things by ditching the Colonials. Will the final five show their mettle and stand by Adama and Co. — or are they really fair-weather friends? —Michael Chant