Sheldon: And to think, I was about to waste the last of my good haemorrhoid cream on you.

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

Stuart: Here, Sheldon, I pulled the new Hellboy for you. It's mind-blowing.
Sheldon: Excuse me. Spoiler alert.
Stuart: I didn't spoil anything.
Sheldon: You told me it's mind-blowing.So, my mind is going into it pre-blown. And once a mind is pre-blown, it cannot be re-blown.
Stuart: I'm sorry.
Sheldon: Said the Grinch to Christmas.

Sheldon: She was a girl who was my friend who is now a girl who is not my friend.
Penny: Wow. That's like the worst country song ever.

Penny: Well why don't you go to the movies then?
Sheldon: Because who would be there to perform the Heimlich maneuver if I choke on my popcorn?
Penny: So, don't buy popcorn.
Sheldon: No popcorn at the mo - listen to yourself!

*Sheldon spots Amy Farrah Fowler outside the apartment*
Sheldon: Oh dear... they really do be crazy.

Sheldon: Hey! Look I found my missing neutrino.
Howard: Oh, great! We can take it off the milk carton.

Sheldon: Amy Farrah Fowler, that's the most pragmatic thing anyone has ever said to me.

Sheldon: Amy Farrah Fowler has asked me to meet her mother.
Leonard: Yeah, so?
Sheldon: What does that mean?
Leonard: Well, you know how you're always saying Amy is a girl who is your friend but not your girlfriend?
Sheldon: Uh huh.
Leonard: Well, you can't say that any more.

Amy's Mom: It's nice to meet you too Sheldon, I honestly didn't believe Amy when she told me she had a boyfriend.
Sheldon: I assure you, I am quite real and I'm having regular intercourse with your daughter.
Amy's Mom: What?
Sheldon: Oh yes, We're like wild animals in heat. It's a wonder neither of us has been hurt!
Amy's Mom: Amy? What is he saying?
Amy: You wanted me to have a boyfriend, mother, well here he is! Have to sign off now. My hunger for Sheldon is stirring in my loins.
Sheldon: Oh yes. It's time for me to make love to your daughter's vagina.

Leonard: Have you considered telling her how you feel?
Sheldon: Leonard, I'm a physicist, not a hippie.

Sheldon: You know it just occurred to me, if there are an infinite number of parallel universes, in one of them there's probably a Sheldon who doesn't believe parallel universes exist.
Leonard: Probably. What's your point?
Sheldon: No point. It's just one of those things that makes one of the me's chuckle.

TV Announcer: Up next Babylon 5.
(Sheldon looks at Leonard)
(Penny listening to Sheldon and Leonard argue from her apartment)
Leonard: You're not even watching it.
Sheldon: I can hear it.
Leonard: The dialogue offends you?

Rajesh: Oh,snap.
Sheldon: Snap what?

Sheldon: She is a girl, who is a friend, but she is not, forgive me for doing this, (air quotes) "my girlfriend".