Leonard: Uh, do you remember Penny's ex-boyfriend Zack?
Sheldon: Leonard, I remember all of Penny's ex-boyfriends. If you'd like, I could list them alphabetically.
Leonard: No, thank you.
Sheldon: Fun fact. You would think Zack would be the last one on the list, but she also dated two Zekes.

Raj: I don't like bugs, okay. They freak me out.
Sheldon: Interesting. You're afraid of insects and women. Ladybugs must render you catatonic.

Sheldon: Scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and as it always has, rock crushes scissors.

Sheldon: Why are you crying?
Penny: Because I'm stupid.
Sheldon: That's no reason to cry. One cries because one is sad. For example, I cry because others are stupid, and that makes me sad.

Bernadette: This is so great. Why don't we do it more often?
Amy: Because you have two kids, I have Sheldon, and Penny's apparently in the gym all the time, 'cause damn, look at her!
Bernadette: Yeah, so impressive how you manage to bounce back after having no babies.
Penny: Ah, another reason why we don't do this more often.

Penny: Thank you, but you shouldn't have spent so much.
Zack: Nah. It's cool. I sold my company for a boatload of money. And then I bought a boat. Then I got married. Guess where.
Amy: On your boat?
Zack: No, but that would've been awesome!

Penny: Did-did you send this over?
Zack: I did. I asked for the most expensive one they have. They said it was $200, and I said I want a more expensive one. And then, they said it was $300.
Amy: But it-it was the same-
Penny: Don't.