He is one serious wackadoodle.

Raj: God, I love the smell of paintballs in the morning.
Wolowitz: Yeah, still funny, Raj.

Penny: How can I calm down? I’m gonna lose my whole shopping cart. That’s three hours of picking out shoes just shot to hell.

Leslie: Boy, your heart's racing. I must've really gotten you going.
Wolowitz: Well, it's partly you, partly my transient idiopathic arrhythmia.
Leslie: Sexy.
Penny: Oh, what are we gonna do?
Leonard: We? No, no, no, you had your chance to be we for, like, a year and a half now. Right now, you are you, and you are screwed.

Leonard: There’s no discernible butt print.
Penny: Oh, come on. There, butt print.
Leonard: It’s too small and too perfect.
Penny: Thank you.
Leonard: You’re welcome.

Wolowitz: Ooh, looks like I'm gonna have sex tonight. Hey, baby...
Penny: His right hand is calling him?

Wolowitz: I’m just a bought-and-paid-for sex toy.
Leslie: No. No, not at all. You’re also arm candy.

Sheldon: What’s real? What isn’t? How can I know?