Raj: Did the listing actually saying "Miniature"?
Leonard: (Looking at time machine) I just assumed.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

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!