Leonard: Do I get some sympathy now?
Penny: A little bit. Okay. Let me get this straight. You move in with this guy, he makes you sign a ridiculous roommate agreement, then he walks into your bedroom while you're doing this Joyce Kim, and you still stay?
Leonard: Actually, I couldn't get too mad at him about Joyce Kim.
Penny: Why not?
Leonard: Well, I was doing some government research at the time, you know, military, rocket fuel. It's kind of secret.
Penny: What does that have to do with Joyce Kim?
Leonard: As it turns out, she was a North Korean spy. Luckily, Sheldon drove her out before I revealed anything important. Which I'm not saying I would have.