Howard: Don't you think I should answer the engineering questions? I am an engineer.
Sheldon: By that logic I should answer all the anthropology questions because I'm a mammal.
Leonard: *Explaining the significance of the experiment to Zack* Think about what this represents. The fact that we can do this is the only way of definitively proving that there are man-made objects on the moon, put there by a member of a species that only 60 years before had just invented the airplane.
Zack: *Astonishingly* What species is that?
Howard: *Noticing Raj peeking through someone's window using the telescope* Oh, Raj, no.
Wolowitz: Billions of dollars have gone into inventing the Internet and filling it with pictures of naked women,so we don't have to peep through windows.
Raj: I like the new look
Howard: Thanks.....I call it the Clooney
Raj: I call it the Mario and Luigi but whatever
Sheldon: That seems like an awful lot of trouble to go through for intercourse. Don't you have access to women who will do it for money?
Leonard: She didn’t dump me. We were just in different places in the relationship.
Sheldon: I fail to see how a relationship can have the qualities of a geographical location.
Wolowitz: It’s very simple, Leonard was living in a little town called “Please don’t leave me”, while Penny had just moved to the island of “Bye-bye”!
Leonard: Howard brought a date?
Sheldon: A more plausible explanation is that his work in robotics has made an amazing leap forward.
Ramona: You are so witty!
Sheldon: Aren't I?
Sheldon: Given that Saint Valentine was a 3rd century Roman priest, who was stoned and beheaded, wouldn't a more appropriate celebration of the evening be taking one's steady gal to witness a brutal murder?
Penny: Look, can we just forget about this extra stuff and can you just tell me what Leonard does?
Sheldon: Alright. Leonard is attempting to learn why subatomic particles move the way they do.
Penny: Really? That's it? Well, that doesn't sound so complicated.
Sheldon: It's not... it's why Leonard does it.