Sheldon: Can I at least kick down the door?
Leonard: You're welcome to try, but the other day, it took you 15 minutes to get into a FedEx box.

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: 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.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

Penny: Give my friend his stuff back.
Tod Zarnecki: I don't know what you're talking about.
Penny: Well then good news. Today's the day a girl's finally going to touch you in your little special place. *Kicks him in the groin*

Raj: Come on, dude, bros before ... my sister.

Sheldon: I've never said these words before, but good job, Howard.