Raj: Excuse me, I can't be drinking, I'm about to make an important scientific discovery here.
Howard:What? Galileo did his best work while drinking wine.
Raj: How do you know that?
Howard: He was Italian, it's a reasonable assumption.
Raj: Dude, can you even open your mouth without saying a cultural stereotype?
Howard: I'm sorry. Galileo drank diet sprite.

Howard: You know, I'm really glad you decided to learn Mandarin.
Sheldon: Why?
Howard: Once you're fluent, you'll have a billion more people to annoy instead of me.

Bernadette: Maybe we should get one of those machines to help her up the stairs.
Howard: You mean a forklift?

Sheldon: Sheldon Cooper does not cry.
Howard: That's true, you'd rust.

Leonard: You'll never guess what just happened.
Sheldon: You went out in the hallway, stumbled into an inter-dimensional portal, which brought you 5,000 years into the future, where you took advantage of the advanced technology to build a time machine, and now you're back, to bring us all with you to the year 7010, where we are transported to work at the think-a-torium by telepathically controlled flying dolphins?
Leonard: No.
Sheldon: Awww.
Leonard: Penny kissed me.
Sheldon: Who would ever guess that?

Sheldon: I'd like to go over some proposed changes to the roommate agreement, specifically to address Penny's annoying personal habits.
Penny: Oh my God! What personal habits?
Sheldon: I have a list. FYI overuse of the phrase "Oh my God" is number 12.

*Leonard is kissing Penny, and Penny's dad enters*
Penny: Come on, honey, not in front of my dad.
Penny's dad: Relax, I've seen her do a lot worse with a lot stupider.