Penny: Okay, instead of protecting me, why don't you try being excited when something good happens?
Leonard: I'm always excited for you. I'm excited that you found this new job where you're making decent money.
Penny: Decent? I make twice what you make.
Leonard: Wait, twice?
Penny: Yeah.
Leonard: Like times two, twice?

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.

Sheldon: It reminds me of when my stupid brother and sister would build forts in the living room, and wouldn't let me in. I hated that so much.
Amy: You know, there's nothing I can do about getting you invited to the symposium, but if you wanted we could build a fort.
Sheldon: Isn't that a little juvenile?
Amy: More juvenile than this? *Puts up picture of smiling Sheldon to her face*

Josh: So, I have to ask, was the robot sexy?
Howard: It was actually just a mechanical hand.
Josh: 'Cause that's all you need, right?
Howard: You are my brother.

Leonard: Well, you can spend the rest of the day being bitter about this--
Sheldon: Agreed.
Leonard: I was going to say "or," but why bother?