Leonard: It's like when I started doing chin-ups. I didn't want you to see until I could do one. FYI, really close.

Raj: I'm sick of people being mean on the Internet.
Howard: I think the anonymity makes everyone feel like they can say things they'd never say to your face.
Sheldon: Interesting. I can't think of a single thing I wouldn't say to someone's face.
Leonard: Never noticed that about you.

Leonard: Do you really want him to write back?
Sheldon: I do. And no matter how he responds, I'm going to destroy him with a picture of a bored cat saying "Oh, really?"
Leonard: Mee-wow.

Leonard: "Upon review, I've changed my mind about the Cooper-Hofstadter hypothesis that space-time is like a super-fluid. In fact, it's inspired me to come up with my own theory. Maybe space-time is like two clowns with their heads in a bucket. Much like Cooper and Hofstadter."

Leonard: One calls it insightful and innovative. We're insightful and innovative.
Sheldon: Nice to meet you, Mr. Insightful.
Leonard: Ah, the pleasure is mine, Mr. Innovative.

Sheldon: I like it. I think you're on to something.
Leonard: Really? You're not messing with me?
Sheldon: Not at all. In fact, I have got something for just such an occasion. I was starting to think I'd never get a chance to give it to you. Good job!
Leonard: You're giving me a sticker?
Sheldon: Not just a sticker. That's a sticker of a kitty saying "Mee-wow".
Leonard: I'm not a preschooler.
Sheldon: Fine, I'll take it back.
Leonard: I earned this. Back off.

Alex: I'm Alex, Dr. Cooper's new assistant.
Leonard: Ah, congratulations and may God have mercy on your soul. I'm Leonard.

Leonard: My dad was an anthropologist. The only father-son time he spent was with a 2,000-year-old skeleton of a Etruscan boy. I hated that kid.

Leonard: You, uh, moving in to the apartment on the fifth floor?
Cole: No, I was just visiting a friend.
Leonard: Oh, cool. The cute blond on four?
Cole: Yeah, you know her?
Leonard: I see her around. I like to keep my distance because her boyfriend is a pretty scary dude.
Cole: Really?
Leonard: Yeah. He's ganged up.
Cole: She told me he's a scientist.
Leonard: That's the name of his gang. The Scientists. They're crazy.
Cole: Well, thanks for the tip.
Leonard: No problem, brother. Stay frosty.

Alex: Oh, hello, Dr. Hofstadter.
Leonard: Hey, Alex, call me Leonard. Dr. Hofstadter is my father. And my mother. And my sister. And our cat. Although I'm pretty sure Dr. Boots Hofstadter's degree was honorary.

Leonard: Who are you talking to?
Penny: Oh, just this guy I met at school.
Leonard: oh, great. We're still dating, right?
Penny: Relax. He's just a friend. We're doing an oral report together. He's really nice.
Leonard: I'm sorry, what was that? I had a little stroke after oral.

Penny: What am I supposed to say?
Leonard: Say "Can't talk right now, hanging with my boyfriend. England sucks. You suck. USA number one."

Leonard: I know he can be a lot of trouble, but when I see him laying here asleep like this, I just think, how easy it would be to hold a pillow over his face.

Raj: Where's Sheldon?
Penny: Date night.
Leonard: That can't be much fun for Amy. You know at work today he tried his first Redbull.
Bernadette: What happened?
Leonard: He chased a squirrel around the quad for a while. And then threw up in my car.

Raj: You know what, I think it's a little weird that you remember me saying all these things. Maybe the truth is you're jealous of all my relationships.
Howard: Oh. Maybe I am. Who wouldn't want to the girl - or possibly dog - to hear the words "You're so lucky. You have the shiniest hair."
Leonard: That is a tough one. I know he brushes both of them.