Leonard: I know shopping cheers you up, but it's not really my thing.
Penny: Well, how about this helicopter you control with an iPad?
Leonard: Does it have a camera in it?
Penny: It does have a camera in it.
Leonard: Baby's listening.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Leonard: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Leonard: [to a "smiling" Sheldon] We're here to see Koothrappali, not kill Batman.

Penny: I mean, who even reads Scientific American?
Leonard: It's kind of a big deal.
Penny: If it's such a big deal, how come the biggest celebrity they could get for the cover is a molecule?

Sheldon: Is it my fault I have a much bigger reputation than he does?
Amy: It's not your fault.
Sheldon: Is it my fault that my name came first on the paper alphabetically?
Amy: Not your fault.
Sheldon: Is it my fault that when the reporter cited me as the lead scientist, I didn't correct him?
Amy: Hey look at that pretty bird.

Howard: All Ma's food is going to be ruined.
Bernadette: Why don't we take it home and put it on our freezer?
Raj: You don't want to do that. Refreezing not only removes moisture, but it creates ice crystals in the fibres of the meat that can compromise its taste and texture. What? I saw a teachable moment. I dropped some culinary science.