Penny is always the odd one out in The Big Bang Theory. At the start of the series, she’s the only woman in a friend group full of scientists who wear their passion for pop culture on their sleeves.

Kaley Cuoco was one of the main stars on "The Big Bang Theory." During the show's run, she had a very personal way of capturing memories on set.

The Big Bang Theory is, at its heart, about relationships. The geek culture references, cameos, and science speak are dressings, and funny ones at that. But from the very beginning, the series set ...