The Sing-Off (8pm, NBC) - The 10 remaining groups perform guilty-pleasure songs before two acts are eliminated.
Terra Nova (8pm, Fox) - A "Sixer" girl seeks asylum in Terra Nova. Taylor suspects there's at traitor in the ranks and Mira schemes to reclaim a possession.
2 Broke Girls (8:30pm, CBS) - Max and Caroline throw a '90s-themed party at the diner to raise money for their cupcake business, but Caroline is horrified when her rich ex-boyfriend attends the party.
Bored to Death (9pm, HBO) - On the run from police, Jonathan and Ray turn to Howard (Patton Oswalt) for help with trying to find out who framed Jonathan for murder, while George runs interference for them in his own inimitable, marijuana-induced way.
Enlightened (9:30pm, HBO) - Despite being banished to a dead-end job in the basement of Abaddonn, Amy tries to impress a human resources representative with evidence that the company needs to redefine its mission. Elsewhere, Amy seeks to convince Levi to change his ways.
Castle (10pm, ABC) - An insurance investigator assists Castle and Beckett with a homicide case stemming from the theft of a costly sculpture, and a museum benefactor becomes one of the murder suspects.
Hawaii Five-0 (10pm, CBS) - The Five-0 investigates the murder of a volleyball coach and the probe leads the team to discover more bad news about Kono and her ongoing legal problems.
Brooke Cain isn't always proud of the number of hours she logs in front of the TV, but her loss of brain cells can be your gain. From reality shows to sitcoms to the more serious stuff, Brooke keeps her DVR smoking so that she can help keep you in the know. Brooke also tweets for Happiness is a Warm TV (you can follow