Penny: Hey, you ready to go?
Leonard: Hang on.
Penny: What are you doing?
Leonard: Oh, I found a scratch-and-sniff book about wine tasting. It teaches the different flavor notes to look for.
Penny: You actually smell the wine?
Leonard: I mostly just smell my nasal spray.
Penny: Are your sinuses acting up?
Leonard: Since my preschool got a bunny.

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?

Leonard: Hey, did you ever think about the military applications for the guidance system?
Sheldon: Of course.
Leonard: Does it bother you?
Sheldon: No, it did at first. But then I talked it through with Frank and Alicia, and they really helped put things into perspective.
Leonard: Who are these people?
Sheldon: Leonard, friends are like toilet paper. It's good to have extras under the sink.

Raj: Yeah, okay, just do me a favor and stop talking about how great Claire is.
Zack: Anything for you, my little foreign friend.

Raj: Hey, dude, you're killing me with Claire.
Zack: What are you talking about?
Raj: I mean, come on, look at you. You're classically handsome, you've got a swimmer's body. Next to you, I look like me.