Big Bang Theory (8pm, CBS) - The fifth season ends with Howard and Bernadette deciding to get married before his NASA mission, which causes the gang to scurry into overdrive to stage the wedding. NASA astronaut Mike Massimino has a cameo as himself.
The Vampire Diaries (8pm, CW) - The third season concludes with Elena wishing she could go back to simpler times when her parents were alive.
Community (8pm, NBC) - Abed develops a conspiracy theory and determines that Dean Pelton is an impostor. His search for the truth lands him in mandatory therapy sessions after he's caught sneaking around campus.
Grey's Anatomy (9pm, ABC) - The residents make their postresidency decisions. Also, Mark tells Derek that he's torn between Lexie and Julia, and Arizona encourages a childhood friend to have surgery.
The Secret Circle (9pm, CW) - In the Season 1 finale, Cassie and Diana tap into dark magic to help Faye fight off the Witch Hunters.
The Mentalist (10pm, CBS) - Jane receives a message from Red John on the eighth anniversary of the deaths of his wife and daughter.
Scandal (10pm, ABC) - As Gideon investigates Amanda's past, flashbacks recall the contentious primary race between Fitz and Sally Langston, who is now vice president. We also see how Olivia and Fitz first met on the campaign trail and how each of her associates joined her team.

Community 8pm, NBC) - The death of a classmate gives Britta a chance to play counselor to the others by using the psychology lessons she's recently learned, but Jeff appears unaffected by the loss.
American Idol (8pm, Fox) - A performance round is held in Las Vegas.
The Vampire Diaries (8pm, CW) - Elena attends a formal ball at Klaus' newly renovated mansion and learns of a horrifying plan that could lead to numerous deaths.
30 Rock (8pm, NBC) - Liz is forced to do damage control when a crude rant by Tracy leaks on the Internet. Also, Kenneth and Jenna once again enlist Kelsey Grammer (playing himself) to help with a problem.
The Vampire Diaries (8pm, CW) - Klaus threatens violence unless Stefan returns the coffins containing his family members, but Elena tries to strike a deal with him.
Parks and Recreation (8:30pm, NBC) - A local group predicts the end of the world is near, so Tom decides to throw a huge party and April helps Andy check items off his "bucket list."
