Leonard: Face it, Raj, we crashed and burned tonight.
Mrs. Latham: Oh, you didn't do that badly.
Leonard: Mrs. Latham, the first machine I turn on in the morning is the helium-neon laser, 'cause it needs to warm up.
Mrs. Latham:: I no longer care, dear.

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

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.

Penny: Good morning, slut!
Leonard: What?
Penny: Oh, please! I recognise the walk of shame when I see it. All you're missing is a little smeared mascara and a purse with panties wadded up in it!

Sheldon: Given how much time you spend engaging in pointless self-abuse, you might consider, just this once, using your genitalia to actually accomplish something.

Sheldon: An entire dinner to talk about your research? Where you going? The drive thru at Jack In The Box?