Penny: I mean, who even reads Scientific American.
Leonard: It's kind of a big deal.
Penny: If it's such a big deal, how come the biggest celebrity they could get for the cover is a molecule?

Sheldon: Would you like to play a physics car game I invented called "I Can't Spy"? It's all the nail biting tension of "I Spy," but the added fun of sub-atomic particles and waves outside the visible spectrum.
Leonard: If it's half as much fun as "One Times Ten to the Fourth Bottles of Beer on the Wall," I'm in.

Sheldon: Play that funky music, white boy!
Leonard: I'm surprised you know that reference.
Sheldon: What reference?

Sheldon: Is that the attitude to helped you get Penny?
Leonard: No, but I don't have three years to make that gate feel sorry for me.

Wil Wheaton: Leonard, a moment ago, you were dead set against Penny resuming her acting career, but now you're all for it. Is it fair to say she played you like a violin?
Leonard: Yes it is, Wil.

Sheldon: [singing] The itsy bitsy spider is not an insect at all. Because it has eight legs and two body parts.
Leonard: That’s pretty cool, Sheldon.
Sheldon: Thank you. Do either of you know Beyonce? I’d love her to get behind it.

Sheldon: Aren't you afraid of being blinded?
Leonard: How would I be blinded?
Sheldon: At the end of the ceremony, all the students throw those pointy hats in the air. It's all pomp and circumstance until someone loses an eye.

Penny: Think we'll have time to visit your mom while we're there?
Leonard: Yes. We'll also have time to put my junk in a garlic press, but I'm not doing that either.

No need to. As soon as she flies into California air space, I'll feel a disturbance in the force.

Gallo: I'm curious. Are you related to Dr. Beverly Hofstadter?
Leonard: She's my mother. Do you know her?
Gallo: Not personally, but I have read all of her books.
Leonard: Then you know her better than I do.
Gallo: Well I'm not so sure about that. But I can tell you I do not agree with her theories on child rearing at all.
Leonard: Really. Any chance you find them cold, cruel and unsuitable for Innocent little boys who just want to be happy?
Gallo: Well, I didn't want to say it...
Leonard: No, say it! Say it! Rent a plane, write it in the sky.

Leonard: I'm not going to make a fake appointment with a psychiatrist. What would I say is wrong with me?
Koothrappali: Low self esteem.
Howard: Social anxiety.
Sheldon: Sexual insecurity.
Leonard: None of that is true.
Penny: Denial. See sweetie, the list goes on and on.

Penny: Leonard? Coffee?
Leonard: Black and strong like Luke Cage.
Penny: I'm too tired to even be disturbed by that.

TBBT Quotes

Oh, Bernadette, please play my clarinet.

Raj's poem

Sheldon: I'll have a diet Coke.
Penny: Can you please order a cocktail? I need to practice mixing drinks.
Sheldon: Fine... I'll have a virgin Cuba Libre.
Penny: That's... rum and Coke without the rum.
Sheldon: Yes, and would you make it diet?