Professor Proton: Can a clock be powered by an ordinary potato? I hope so, boys and girls, or this is going to be a really boring episode.

Adult Sheldon: That was the first time I held my father's hand. I wouldn't touch my brother's hand until seventeen years later, thanks to the invention of Purell.

Mary: You understand that some people are going to be intimidated by you, because of how smart you are?
Sheldon: Or maybe they'll recognize my intellect and make me their leader.

Sheldon: I smell ammonia. They must've done a thorough cleaning recently. I like that.