A flashback to when Leonard first moved in with Sheldon and they signed the roommate agreement.
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Sheldon runs into a character played by Mayim Bialik on the 5/17/10 episode of The Big Bang Theory. Might she be the one for him?
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You gotta love this guest-starring appearance on The Big Bang Theory: that's former sitcom star Mayim Bialik!
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A picture after Wil Wheaton just bowled as Sheldon prepares to counter.
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Wil Wheaton calls out Sheldon as the two of them meet in the bowling alley.
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Sheldon has a shirt made that says "The Wesley Crushers" for his bowl off with Wil Wheaton. Get it? No? Wheaton played Wesley on Star Trek.
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Sheldon goes up against Wil Wheaton in the ultimate bowl off between rivals.
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Sheldon goes up against his nemesis, a characterized version of Wil Wheaton, in bowling on The Big Bang Theory.
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TBBT Quotes

Penny: Here's a question-- as an alien pretending to be human, are you planning to engage in any post-prom mating rituals with Amy?
Sheldon: There are post-prom mating rituals?
Penny: Not always. Unless your date drives a van with an air mattress, then always.
Sheldon: Well, if it's part of the prom experience, then I'm open to it.
Penny: You're kidding.
Sheldon: I may be an alien, but I have urges.If Amy wants to copulate by firing her eggs into space, well, then, I will happily catch them with the reproductive sac on my upper flermin. I'm not the best at reading facial cues, but I can see that you're a little turned on.

Sheldon: If you could wake up tomorrow having gained any one quality or ability, what would it be?
Penny: Well, not to steal from the Bible, but turning water into wine sounds pretty good.