Howard: Howard Wolowitz, department of engineering, co-designer of the International Space Station's Liquid Waste Disposal System.
Ramona: Ew.

Howard: You know, the Pishkin-Wolowitz Liquid Waste Disposal System is turning a few heads as well.
Ramona: Again, ew.

Penny: Dr. Sheldon Cooper?
Ramona: We're having dinner.
Penny: Sheldon Cooper? Tall, thin, looks a little like a giant praying mantis.
Ramona: He is cute, isn't he?

Leonard: On the other hand, I think Sheldon might be the larval form of his species, and some day he'll spin a cocoon and emerge two months later with moths wings and an exoskeleton.
Penny: Okay, well, thanks for the nightmares.

Leonard: Oh, then I think you'll appreciate what I got you.
Penny: Okay. 101 Totally Cool Science Experiments for Kids.
Leonard: You know, 'cause you're so into science.

Sheldon: What it is is a cacophonous assault of eucalyptus, bayberry, cinnamon and vanilla. It's as if my head were trapped in the pajamas of a sultan.

Dave: I don't know how you live next door to that without doing something about it.
Leonard: Actually, science is my lady.

Leonard: Oh, a gift certificate for motorcycle lessons. Very thoughtful.
Penny: Yeah, and I checked. Not letting the bike fall on you while standing still is lesson one.

Leonard: I've been offering to show you around for a year and a half. You always said you had yoga.
Penny: I never said that.
Leonard: Maybe I heard you wrong. A lot of words sound like yoga.

Penny: Dave is not smarter than you. He's an idiot.
Leonard: Really? Why would you say that?
Penny: Because a smart guy takes the nude photos of his wife off his cell phone before he tries to take nude photos of his girlfriend.
Leonard: He tried to take nude photos of you?
Penny: That's what you took from that? The guy is married.

Howard: That doesn't count. Do over! Do over!
Sheldon: There are no do-overs in Wii bowling.
Howard: There are always do-overs when my people play sports.

Raj: Whoa. Humongous man crush, dude.

Howard: Yep. It's officially a bro-mance.

Raj: "Kandorian dry cleaner-" I give up, you can't have a rational argument with this man.

Leonard: Wow, teasing the guys at the Apple Store seems a little redundant now.
Sheldon: I don't follow.
Leonard: I wouldn't expect you to.