Penny [about his mom]: You can't let her get into your head
Leonard: It's too late for me, my head is her summer house

Mrs. Hofstadter [about Penny]: If you want to have sex with that woman, find out what kind of cologne her father wore
Leonard: Hello mother

Leonard: Okay, is everyone clear on the plan?
Wolowitz: Yes. Koothrappali is going to wet himself, I'm going to throw up, Sheldon is going to run away, and you're going to die. Shall we synchronize our watches?

Leonard: What was the plan?
Penny: Um, waitress for six months and then become a movie star.
Leonard: Was there a Plan B?
Penny: TV star.

Penny: Dave is not smarter than you, he's an idiot.
Leonard: Really? Why would you say that?
Penny: Because a smart guy takes the nude photos of his wife off his cell phone before he tries to take nude photos of his girlfriend.
Leonard: He tried to take nude photos of you?
Penny: That's what you took from that?

Leonard: Every time I try to talk to her about moving out she cries, and we have sex.
Raj: You're lucky. With me it's usually the other way around

Penny: You don't always have to go along with what the woman wants.
Leonard: Huh.
Penny: What?
Leonard: Nothing... just re-thinking my whole life

Penny: I am going to introduce your friend to a world of hurt.
Leonard: You don't want to get into it with Sheldon. The guy is one lab accident away from being a super villain

Raj: We now have the address of the Top Model house.
Howard: God bless you, Google Street View—registered trademark.
Leonard: Okay, for the record, what you guys are doing is really creepy.
Wolowitz: You know what? If it's creepy to use the Internet, military satellites, and robot aircraft to find a house full of gorgeous young models so that I can drop in on them unexpectedly, then fine, I'm creepy.

Leonard: Put it on the agenda.
Sheldon: You have to make a motion to put it on the agenda.
Leonard: Oh, I'll make a motion, but you're not going to like it

Leonard: Just apologize to him, okay?
Penny: What? I'm not going to apologize to that nut-case.
Leonard: Come on, it's easy. He'll even tell you what to say

Wolowitz: Over the years, we've formulated a number of theories about how he might reproduce. I'm an advocate of mitosis.
Penny: I'm sorry?
Wolowitz: I believe one day Sheldon will eat an enormous amount of Thai food and split into two Sheldons.
Leonard: On the other hand, I think Sheldon might be the larval form of his species and someday he'll spin a cocoon and emerge two months later with moth wings and an exoskeleton

TBBT Quotes

Oh, Bernadette, please play my clarinet.

Raj's poem

Sheldon: I'll have a diet Coke.
Penny: Can you please order a cocktail? I need to practice mixing drinks.
Sheldon: Fine... I'll have a virgin Cuba Libre.
Penny: That's... rum and Coke without the rum.
Sheldon: Yes, and would you make it diet?