Supernatural (8pm, CW) - Two back-to-back episodes close out the sixth season tonight. In the finale, the memory-blocking wall inside of Sam's head that keeps his darkest memories from him comes crashing down and he struggles to deal with the consequences.
Friday Night Lights (8pm, NBC) - Coach Taylor is praised in a popular magazine, a figure from Vince's past makes a demand, Luke digests the news about TMU, and Julie's return to college is delayed.
Flashpoint (8pm, CBS) - Mike fears his former mentor may be implicated in a case that involves corruption, drug dealers and an attempted gang execution.
Real Time with Bill Maher (10pm, HBO) - Amy Chua and Zach Galifianakis are the interview guests tonight. Last time Galifianakis was on the show, he made headlines when he lit up and smoked a joint to illustrate his point about the legalization of marijuana. He also discussed his uncle Nick Galifianakis' failed senate run against Jesse Helms. I'm sure he's on tonight to promote 'Hangover 2,' but with him, you never know what else might come up. Other guests include author Reza Aslan, commentator Dylan Ratigan, and journalist Gillian Tett.
20/20 (10pm, ABC) - A report on infomercials and the "as seen on TV" products they promote. Includes interviews with celebrity product spokespersons and infomercial entrepreneur A.J. Khubani.