Leonard: How did you know my birthday's Saturday?
Penny: I did your horoscope, remember? I was going to do everybody's until Sheldon went on one of his typical psychotic rants.
Sheldon: For the record, that psychotic rant was a concise summation of the research of Bertram Forer, who, in 1948, proved conclusively through meticulously designed experiments that astrology is nothing but pseudoscientific hokum.
Penny: Blah, blah, a typical Taurus

Penny [on phone]: How about this, you keep him there a little longer, and when you get to the party, I'll point out which of my friends are easy.
Wolowitz: ... Don't toy with me, woman.
Penny: I got a hot former fat girl with no self-esteem, I got a girl who punishes her father by sleeping around, and an alcoholic who's two tequila shots away from letting you wear her like a hat.
Wolowitz: Thy will be done

Leonard [about the time machine]: The lights flash, and the dish spins. You wanna try it?
Penny: No, I don't wanna try it! My God, you are grown men! How could you waste your lives with these stupid toys and costumes, and comic books, and-and... now that-that...
Sheldon: Again—time machine.
Penny: Oh, please, that's not a time machine. If anything, it looks like something Elton John would drive through the Everglades

Penny [to Leonard]: Look, you are a great guy, and it is the things you love that make you who you are.
Wolowitz: I guess that makes me large breasts

Sheldon: You hypocrite!
Penny: What?
Sheldon: Little Miss 'Grown-ups don't play with toys', if I went into that apartment right now, would I not find Beanie Babies? Are you not an accumulator of Care Bears and My Little Ponies? And who is that Japanese feline I see frolicking on your shorts? Hello, Hello Kitty!

Penny: What actor holds the record for being named People magazine's Sexiest Man Alive?
Sheldon: William Shatner!
Leonard: I don't think it's Shatner.
Sheldon: Then it's got to be Patrick Stewart

Leonard: Sheldon, you have to let somebody else answer.
Sheldon: Why?
Penny: Because it's polite.
Sheldon: What do manners have to do with it? This is war. Were the Romans polite when they salted the ground of Carthage to make sure nothing would ever grow again?

[Raj whispers in Wolowitz's ear]
Penny: What did he say?
Wolowitz: He compared Sheldon to a disposable feminine cleansing product one might use on a summer's eve.
Penny: Yeah, and the bag it came in

Sheldon: In Texas, when a cow stops giving milk, they don't continue feeding her. They take her out and shoot her between the eyes.
Penny: I'm confused. Did Sheldon stop giving milk?

Wolowitz: We need a hot 15-year-old Asian girl with a thing for smart guys.
Penny: What?
Leonard: Howard, that's racist. Any fifteen year old girl will do the trick

[at The Cheesecake Factory]
Penny: Why didn't you just have soup at home?
Sheldon: Penny, I have an IQ of 187. Don't you imagine if there were a way for me to have soup at home, I would have thought of it?
Penny: You can have soup delivered.
Sheldon: I did not think of that

Sheldon: Anyway, the housekeeper in the faculty residence didn't speak any English. When I finaly managed to convince her I was sick, she said, "Möchtest du eine Darmspülung?"
Penny: What does that mean?
Sheldon: Based on what happened next, I assume it means, "Would you like an enema?"

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?