Howard: What kind of secret does Sheldon have to encrypt?
Raj: He's always been very cagey about what he puts in his egg salad to make it so tasty.
Howard: It's paprika.
Raj: Really? Well, okay, one mystery solved.

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.

Howard: Forty-three. What is forty-three? Besides my mom's neck size.
Raj: It's the atomic number for technetium.
Howard: That stuff's radioactive.
Raj: Do you think he's building a bomb?
Howard: It took him two years to put together that Lego Death Star. I'm not worried.

Penny: Hey, shouldn't you be out with your gang, spray painting equations on the side of buildings?
Leonard: Come on, I'm sorry.

Leonard: It's hard sometimes. Everywhere you go, guys hit on you, even if I'm standing right there. And they're all taller than me. Why is everyone taller than me? You know what, this is all in my head. It's my problem, not yours.
Penny: Leonard, why do you always do this? Listen to me, you're the one I'm with. You know I love you. So will you please relax, because you're driving me crazy.
Leonard: You know that's the first time you ever said you love me.
Penny: Yeah.
Leonard: We're just supposed to pretend it's not a big deal?
Penny: That's exactly what we're gonna do, because you're about to make me cry. And we both know if I start crying, you're gonna start crying.
Leonard: You're right, I should go.

Raj: That's good quality video.
Howard: It better be. It's the same camera for the Mars rover.
Raj: How did you get your hands on that?
Howard: Million dollar camera. Ten dollar lock.

Sheldon: *knock knock knock* Wil Wheaton!
*knock knock knock* Wil Wheaton!
Wait, how many was that?

Sheldon: Ooh, now that is a treat that's hard to beat. Get the Mad Hatter on the horn. I'm having a tea party!

Sheldon: *knock knock knock* Amy.
*knock knock knock* Amy
*knock knock knock* Angry Amy.

Sheldon: Eat one of your Luna bars. Very often when women think they're angry, they're really just hungry.

Sheldon: Someday scientists will discover that second X chromosome contains nothing but nonsense and twaddle.

Sheldon: My fists are not up because I'm milking a giant invisible cow.

Wil Wheaton: No offence, but I've been acting since I was a kid. I think I can handle a web show without a lot of direction.

Amy: And action.
Wil Wheaton: And cut! You realize I'm doing this for free, right?
Amy: Yes, and so far we're still not getting our money's worth.