Check out highlights from The Big Bang Theory Season 6 in this video. It debuted at Comic-Con 2013.
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The Big Bang Theory Season 6 Quotes

They can't just cancel a show like Alphas. You know? They have to help the viewers let go. Firefly did a movie to wrap things up. Buffy the Vampire Slayer continued on as a comic book. Heroes gradually lowered the quality season by season till we were grateful it ended.

Sheldon

Raj: Okay, here's another one: if a zombie bites a vampire, and the vampire bites a human, does the human become a vampire or a zombie? Or, a zompire?