Kaley Cuoco stars as Penny, Sheldon and Leonard's beautiful next door neighbor.  Penny is an aspring actress that currently works at the local Cheesecake Factory.

Penny moved across the halls from the boys after her split from her boyfriend of four years, Kurt.  She briefly dated Sheldon, but it did not work out due to her insecurity about her intelligence.

Penny Quotes

Sheldon: I'm a physicist. I have a working knowledge of the entire universe and everything it contains
Penny: Who's Radiohead?
Sheldon [after twitching for a minute]: I have a working knowledge of the important things

Penny: What?! A few thousand people listen to you talk about nerd stuff?
Wil Wheaton: Again, right in the ears, straight to the feelings.

TBBT Quotes

Sheldon: Are you still mad about the sperm bank?
Leonard: No!
Sheldon: Do you want to hear an interesting thing about stairs?
Leonard: Not really.
Sheldon: If the height of a single step is off by as little as two millimeters most people will trip.
Leonard: I don't care—two millimeters?! That doesn't seem right.
Sheldon: No, it's true! I did a series of experiments when I was twelve; my father broke his clavicle.

Penny, there's only one cookie with something in the middle that solves life's problems, and that's an Oreo. Or a Nutter Butter, if you're in a pinch.

Sheldon