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

The Big Bang Theory Season 6 Quotes

Sheldon: Lipid residue. An anal autograph. A colon calling card, if you will.
Cleaner: Tuesday okay?

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