8 p.m., CBSNeil Patrick Harris) uncovers another gem from Robin’s (Cobie Smulders) past—apparently Robin Sparkles once starred on a Canadian kids’ show called Space Teens with another pop idol, Jessica Glitter (Nicole Scherzinger).
8 p.m., NBCZachary Levi) tries to impress Sarah (Yvonne Strahovski) by taking on a dangerous assignment with an over-zealous agent, played by guest star Rob Riggle. Meanwhile, the Buy More employees try to figure out Greta’s true identity. Summer Glau and Richard Chamberlin also guest star.
9 p.m., CWEd Westwick) hosts the crazy party at his apartment, and Serena’s (Blake Lively) weird behavior stumps Dan (Penn Badgley) and Nate (Chace Crawford).
10 p.m., CBS
Season 1 finale, 10 p.m., SHOLaura Linney) must come to terms with her diagnosis after Dr. Todd (Reid Scott) reveals that the bee treatments aren’t working. Plus, Sean (John Benjamin Hickey) and Rebecca (Cynthia Nixon) reconnect over a shared secret.
Also on the airwaves...
Dancing with the Stars, 8 p.m., ABC
House, 8 p.m., FOX
90210, 8 p.m., CW
Rules of Engagement, 8:30 p.m., CBS
Two and a Half Men, 9 p.m., CBS
Lie to Me, 9 p.m., FOX
The Event, 9 p.m., NBC
In Treatment, 9 & 9:30 p.m., HBO
Cake Boss, 9 p.m., TLC
Mike & Molly, 9:30 p.m., CBS
Castle, 10 p.m., ABC
Chase, 10 p.m., NBC
Hoarders, 10 p.m., A&E;
Weeds, Season 6 finale, 10 p.m., SHO
Bret Michaels: Life As I Know It, 10 p.m., VH1
Mario Lopez: Saved by the Baby, 10:30 p.m., VH1
NFL Football: Eagles v. Redskins
NHL Hockey: Blues v. Avalanche
NCAA Basketball: Pepperdine v. UCLA, Siena v. Minnesota, Hampton v. Wake Forest
What are you watching tonight?
Follow TV.com writer Stefanie Lee on Twitter: @StefAtTVDotCom