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: Hey, Sheldon, did you change your Wi-Fi password again?
Sheldon: Yes, it's "Penny, get your own Wi-Fi." No spaces.
Sheldon: Why are you crying?
Penny: Because I'm stupid!
Sheldon: Well that's no reason to cry; one cries because one is sad. For example, I cry because others are stupid and it makes me sad.