Leonard: That's actually a valid example. Animals do deliver messages through scent.
Raj: Bees talk to each other by dancing. Whales have their songs.
Leonard: Penny has about 20 different ways of rolling her eyes that each mean something different.

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: *singing in the tune of "Bingo Was His Name-o"* There was a scientist who had a theory, and James Clerk Maxwell was his name-o. J-A-M-E-S, C-L-E-R-K, space, M-A-X-W-E-L-L, and James Clerk Maxwell was his name-o. There was a scientist who had a theory, and James Clerk Maxwell was his name-o. *claps* A-M-E-S--
Leonard: Okay, okay, we get it.

Howard: First take a picture with me.
Bernadette: Why?
Howard: Well, Raj and I always talked about learning how to make cocktails like this together, so I taught myself and I'm putting this on Instagram so he can see it and feel like a turd. Say cheese!

Sheldon: *singing in the tune of "Eye of the Tiger"* It's the eye of the tiger, it's the ear of the bat. It's the whiskers of a catfish and the walrus--
Howard: Hang on. Not that your song isn't terrible-- it is... but how do you mention bats and leave out sonar?
Sheldon: You didn't let me finish. *singing* And also regarding the bat. It has sonar.