Leonard: You put moths in my food!?
Sheldon: For science.

You're far too short to be Darth Vader. You're much more likely to be a turncoat Ewok.

Leonard: You know what happens when you yawn in public...
Sheldon: Everyone will see my oddly shaped uvela.

Raj: Hands off my sister.
Sheldon: Why would I touch her? She's covered in airplane germs.

Sheldon: I assure you I am quite real and I'm having regular intercourse with your daughter.
Mrs. Fowler: What?
Sheldon: Oh yes, we are like wild animals in heat. It's a wonder neither of us has been hurt.

Sheldon: I want you to know that I'm genuinely concerned about your well-being.
Leonard: Thank you.
Sheldon: You're welcome. But it's still no reason to have your feet in my spot.

Leonard: Have you considered telling her your feelings?
Sheldon: Leonard, I'm a physicist, not a hippie.
Leonard: Well let me see if I can explain your situation using physics. What would you be if you were attached to another object by an incline plane, wrapped helicly around an axis.
Sheldon: Screwed.
Leonard: There you go.

Sheldon: Why on earth are you telling me all this?
Leonard: Sometimes you movements are so lifelike I forget you're not a real boy.

Leonard: Why would you want a glow-in-the-dark ant farm?
Sheldon: They do some of their best work at night.

If we lived in the world where slow moving xenon produced light youd be correct. Also, pigs would fly, my derriere would produce cotton candy, and the Phantom Menace would be a timeless classic.

Leonard: ...and when she died, they ate her.
Sheldon: You don't have to sell me on cats, I'm already a fan!

Amy: I'm curious as to why we're not eating alone.
Sheldon: They can't function without me. I'm the social glue that holds this little group together.

TBBT Quotes

Penny: Hey, Sheldon, did you change your Wi-Fi password again?
Sheldon: Yes, it's "Penny, get your own Wi-Fi." No spaces.

Leonard: Hi. I'm Leonard. You are beautiful. You pop, sparkle and buzz electric. I'm going to pick you up at eight, show you a night you will never forget.
Raj: Where are we going?