Leonard: What ya doin' there? Working on a new plan to catch the Road Runner?

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: At my age, do you know how I'm statistically most likely to die?
Leonard: At the hands of your room mate?
Sheldon: An accident.
Leonard: That's how I'm going to make it look.

Penny: You wanna turn yourself into some sort of robot?
Sheldon: Essentially, yes.
Penny: Okay, here's my question: Didn't you already do that?

Leonard: What's a dogapus?
Sheldon: A hybrid dog and octopus. Man's underwater best friend.
Leonard: There's someone working on that?
Sheldon: I was going to. I planned on giving it to myself for my 300th birthday.
Leonard: Wait a minute you hate dogs.
Sheldon: A dogapus can play fetch with eight balls; no one can hate that.