Sheldon: Frankly, Mom, I'm encouraged to see how advanced your group has become -- willing to sail into the ocean without fear of falling off the edge.

Sheldon: You know, the German philosopher Friedrich Nietzsche believed that morality is just a fiction used by the herd of inferior human beings to hold back the few superior men.
Leonard: Thanks, that actually does help.
Sheldon: It's worth noting that he died of syphilis.

Sheldon: This will just take a moment, it's on a five and a quarter inch floppy.
Amy: A floppy disk?
Sheldon: Well, I started the list when I was nine.

Sheldon: [jumps out of the sofa] Bazinga, punk. Now we're even!

Howard: You interested in Amy?
Stuart: Well, I mean she didn't look through me with soul-sucking ball-shriveling hatred and contempt. I like that in a woman.

Mrs. Wolowitz Howard Joel Wolowitz, I've been worried sick for two days and I know you turned off your phone. You open this door right now because I've had it up to here! I have been to the morgue and the hospital, and I spent the last half hour walking up these fakakta stairs.

Leonard: Penny, do you have plans for dinner?
Penny: Why, you guys going somewhere?
Leonard: No, just you and me.
Penny: Have you thought this through?
Leonard: Yes, and I think we should go anyway.

Amy: How did you get into my apartment?
Sheldon: Wow. Is that the kind of nagging I can expect now that you're my girlfriend?

Leonard: It's kinda like the Loch Ness Monster. Maybe there's something there, maybe there isn't. We'll never know but sometimes it's fun to creep yourself out thinking about it.

Sheldon: Gentlemen, I think I've come up with a fun way to get young people interested in science. Physics Mad-Libs. Now, give me a number.
Leonard: Five.
Sheldon: Uh-huh. And an irrational constant.
Howard: E.
Sheldon: And a funny Greek letter.
Raj: Gamma.
Sheldon: I said funny.
Raj: Upsilon?
Sheldon: Good one. And an electrical charge.
Leonard: Positive.
Sheldon: Ha. Perfect. Okay. Get this. Professor Jones told the symposium he had a new method for calculating the mass of a muon. Five times the limit of E to the upsilon as in a ... (laughs uncontrollably) ... Okay. No, no. I'll start over. Professor ... (laughs again).

Mrs. Wolowitz You're right. Who am I kidding? You should have seen me when I was young, Sheldon. The fellas used to line up and bring me boxes of candy. Why did I eat it all? Will you hold me?

Leonard: I missed you.
Penny: You see me all the time. You sure you don't just miss the sex?
Leonard: Well, yeah, the sex with you is pretty great. Have you ever tried it?
Penny: I have. You're not wrong.

Sheldon: I play bongos while walking down the stairs.
*Sheldon falls*
Sheldon: Never play bongos while walking down the stairs

Amy: Sheldon, I'm going to ask you something, and Id like you to keep an open mind. Sheldon: Always.
Amy: At this moment, I find myself craving human intimacy and physical contact.
Sheldon: Oh, boy. You know ours is a relationship of the mind.
Amy: Proposal, one wild night of torrid lovemaking that soothes my soul and inflames my loins.
Sheldon: Counterproposal, I will gently stroke your head and repeat "Aww, who's a good Amy?"
Amy: How about this? French kissing, seven minutes in heaven culminating in second base.
Sheldon: Neck massage, then you get me that beverage.
Amy: We cuddle. Final offer.
Sheldon: Very well. Oh, boy.

Bernadette: And just to be safe, when you talk to him don't bring up Jimmy Carter, gardeners, foreign people, homosexuals, Sean Penn, Vatican II, gun control, organic food, the designated hitter rule, recycling or the fact that you're Jewish.