Howard: The e-mail I got was from the office of Stephen Hawking.
Leonard: You're kidding.
Raj: Why?
Howard: He's coming to the university for a couple weeks to lecture, and he's looking for an engineer to help maintain the equipment on his wheelchair.
Leonard: That's amazing. You'll be like his pit crew. A word of caution, I would not do your Stephen Hawking impression in front of him.
Howard: (imitating Stephen Hawking) You're right. I suppose that could be considered offensive.

Howard: You know, I'm really glad you decided to learn Mandarin.
Sheldon: Why?
Howard: Once you're fluent, you'll have a billion more people to annoy instead of me.

Howard: So you can never take it (the sweater) off?
Leonard: No.
Raj: Not even to sleep?
Leonard: No.
Howard: So you're just an idiot?
Leonard: It's called proving a point.
Howard: Is the point you're an idiot?

Bernadette: Does your mother call you every day at work to see if you had a healthy lunch?
Howard: My mother calls me every day at work to see if I had a healthy bowel movement.

Howard: Sheldon, you're a condescending jerk. Why on earth would I want to do something nice for you?
Sheldon: To go to Jewish heaven.
Howard: Jews don't have heaven.
Sheldon: To avoid Jewish hell?
Howard: Have you met my mother? I live in Jewish hell.

Mrs. Wolowitz It's this dress. When I put my front in, my back pops out. When I put my back in, my front pops out. It's like trying to keep two dogs in a bathtub.
Sheldon: What do you want me to do?
Mrs. Wolowitz We're gonna have to work as a team. Get in here, grab a handful and start stuffing.

Wolowitz: You don't seem to be understanding the English word no. Maybe a different language will help. Russian: Nyet. Chinese: Bu. Japanese: iie. Klingon: qo. Binary-coded ASCII: 01101110 01101111.
Sheldon: It's actually 01100111.