Penny fits right in with the gang as they sit down to eat their signature food... Chinese takeout.
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Penny meets Raj and Wolowitz in the pilot episode of The Big Bang Theory. Wolowitz will begin his lifetime of sleazily hitting on her while Wolowitz is unable to talk to her.
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Sheldon and Leonard are about to experience a new life now that Penny moved in next door. By Sheldon and Leonard we really mean Leonard.
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A picture of Sheldon and Leonard from the series premiere of The Big Bang Theory. Sheldon and Leonard are geeks but Leonard wants more than this socially awkward roommate.
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The Big Bang Theory Season 1 Episode 1 Quotes

Leonard: We need to widen our circle.
Sheldon: I have a very wide circle. I have 212 friends on MySpace.
Leonard: Yes, and you've never met one of them.
Sheldon: That's the beauty of it

Leonard: At least I didn't have to invent 26 dimensions just to make the math come out.
Sheldon: I didn't invent them, they are there!
Leonard: In what universe?
Sheldon: In all of them, that's the point