Penny: Okay, first of all, what you call a gap was nearly three feet wide, I slipped and skinned my knee.
Leonard: Are you okay?
Penny: Second of all, the door to the stairwell of the other building was locked, so I had to go down the fire escape which ends on the third floor, forcing me to crawl through the window of a lovely Armenian family, who insisted I stay for lunch.
Leonard: That doesn't sound too bad.
Penny: It was eight courses of lamb, and they tried to fix me up with their son.

Sheldon: Woman, you are playing with forces beyond your ken.
Penny: Yeah, well your Ken can kiss my Barbie.

Raj: [to Amy] If you were having Sheldon's baby, would you really want him in the room?
Penny: Yeah, if he's in the room when they're making the baby, I'll give you $10.

Penny: I mean, who even reads Scientific American?
Leonard: It's kind of a big deal.
Penny: If it's such a big deal, how come the biggest celebrity they could get for the cover is a molecule?

Sheldon: Are you upset about something?
Leonard: What was your first clue?
Sheldon: Well, it was a number of things. First, the late hour, then you demeanor seems very low energy, plus your irritability.
Leonard: Yes, I'm upset!
Sheldon: Oh. I don't usually pick up on those things. Good for me.
Leonard: Yeah, good for you.
Sheldon: (walks away and then turns back) Oh, wait. Did you want to talk about what's bothering you?
Leonard: I don't know. Maybe.
Sheldon: Wow! I'm on fire tonight.

Leonard: Can I go back and prevent you from explaining that to me?
Sheldon: Same paradox. If you were to travel back in time and, say, knock me unconscious, you would not then have the conversation that irritated you, motivating you to go back and knock me unconscious.
Leonard: What if I knock you unconscious now?
Sheldon: It won't change the past.
Leonard: But it'd make the present so much nicer.

Penny: What the hell's going on?
Sheldon: You hypocrite.
Penny: What?
Sheldon: Little Miss Grown-Ups-Don't-Play-With-Toys! If I went into that apartment right now, would I not find Beanie Babies? Are you not an accumulator of Care Bears and My Little Ponies? And who is that Japanese feline I see frolicking on your shorts? Hello, Hello Kitty!