Sheldon: Do you realise I may have to share a Nobel Prize with your booty call?
Leonard: You know what, I'm being ridiculous. Who cares what Penny thinks? Leslie is a terrific girl. She's attractive, we like each other, she's extremely intelligent.
Sheldon: She's not that intelligent.
Leonard: She fixed your equation.
Sheldon: She got lucky.
Leonard: You don't believe in luck.
Sheldon: I don't have to believe in it for her to be lucky.