The Big Bang Theory

Most of the time, Leonard has no lenses in his glasses.

Floors two, three, and four of Sheldon and Leonard's apartment building are the same set just re-dressed for each scene. This can be seen in the fact that the scuff marks on the moulding are identical on each level as they walk up the stairs.

Jim Parsons audition for the role of Dr. Sheldon Cooper was so good that creator Chuck Lorre immediately asked Parsons to come in for a second one, because Lorre wanted to be 100% sure Parsons was as brilliant as he seemed.