Sheldon: Yeah, the point is Higgs is being celebrated for work he did 50 years ago, so that got me thinking, perhaps I've already hit upon the idea that will win me my Nobel prize.
Leonard: I didn't know they gave Nobel prizes for making boom-boom in the potty.

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?

Bernadette: How you doing, Howie? You feeling a little better?
Howard: Oh, a lot better, thanks. One sec. Listen close, I don't have a lot of time. I need you to go to my house. In my bedroom, you'll find a model rocket. I want you to take it and bring it back to your place.
Bernadette: Okay.
Howard: Step two, build a version roughly fourteen stories high. Fill it full of rocket fuel and come get me. I'll leave the door unlocked.
Bernadette: Howie, honey, maybe you should talk to someone, let them know you're having a little anxiety.
Howard: No, no, I'm fine. No anxiety. We should probably talk in code. From now on, frog is me, sandwich means you and lemon means rocket. So, come on, sandwich, build me a lemon 'cause froggy wants to come home.

Penny: Well, of course he's desirable. I mean, he's great. He's smart, he's sweet and, ooh, in the bedroom, whew, let me tell you he really tries.

Amy: Sheldon told me he had a new assistant named Alex. He didn't mention that Alex was a girl.
Penny: Maybe he didn't notice.