Leonard: Oh, I knew it, Sheldon changed the password.
Penny: Are you sure?
Leonard: Well, the new network name is, "Ha ha ha, now I've got you," so It's either Sheldon or Gargamel from The Smurfs.

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: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Leonard: [to a "smiling" Sheldon] We're here to see Koothrappali, not kill Batman.

Sheldon: If it's like your 3-D chess game, then you're out of your length, width and depth. Amy, get the Neosporin, somebody just got burned.

Leonard: Sheldon, I know what you did, now change the password back.
Sheldon: Well, powder me in sugar and call me a donut, if it isn't Leonard Hofstadter.

Sheldon: It's not my fault I'm bad at sharing; I skipped kindergarten.