Penny: Sheldon, did you have a Christmas tree?
Sheldon: Oh, yes. We had a tree, we had a manger, we had an inflatable Santa Claus with plastic reindeer on the front lawn. And to make things even more jolly, there were so many blinking lights on the house they induced neighborhood-wide seizures.

Sheldon: Hello Penny. I realize you are currently in the mercy of your primitive biological urges. But, as you have an entire lifetime of poor decisions ahead of you, may I interrupt this one?

Leonard: They're gonna get beaten up at that club.
Penny: They're gonna get beaten up at Walgreens.

(Sheldon notices Penny taking Leonard to his bedroom)
Sheldon: What's going on?
Penny: Get your noise-cancelling headphones, 'cause it's gonna get loud.
Sheldon: Oh, not this again.

Leonard: Can I have a napkin.
Sheldon: I'm sorry, no!
Leonard: But you have a whole bunch of napkins.
Sheldon: Yes, I've moved to a four napkin system, lap, hands, face, and personal emergency. If you like, starting tomorrow, I'll add a guest napkin but I'm afraid there's nothing I can do for you today.
*Leonard grabs a napkin.*
Sheldon: Good luck, that's the face napkin.

Sheldon: Oh, by the way, I was watching you sleep for a moment, and I noticed that your snoring seems to be worse when you're on your back.
Penny: Leonard doesn't snore.
Sheldon: I wasn't talking to Leonard.
Leonard (to Penny): Told ya.

Sheldon: There there, everything is going to be fine... Sheldon's here!

Sheldon: There's a fine line between wrong and visionary. Unfortunately, you have to be a visionary to see it.

Leonard: You know what, go to Hell and set their thermostat.
Sheldon: I don't have to go to Hell. At 73 degrees, I'm there already!

Rajesh: Excuse me but I don't think Penny is out of line at all. You don't own her. It's like my girl Beyonce says: If you like it you should've put a ring on it.

*After getting a spare in the bowling match*
Sheldon: Thank you, Jesus! As my mother would say.

Sheldon: But evolution is not opinion, it's a fact. Mary Cooper: And that is your opinion. Sheldon: [to Leonard, Howard and Raj] I forgive you, let's go home.

Sheldon: Hello.
Penny: Hello.
Sheldon: Ok, enough with the friendly banter. I believe you know why I am here.
Penny: Oh, I always figured it was to study us, discover our weaknesses, and report back to your alien overlords.
Sheldon: Yes amusing. Extraordinary intelligence might well appear extraterrestrial to you, but let me be more specific. I believe you know why I am here in the laundry room.

Penny: I always tear up when the Grinch's heart grows three sizes.
Sheldon: Tears seem appropriate. Enlargement of the heart muscle, or hypertrophic cardiomyopathy, is a serious disease which can lead to congestive heart failure.

Howard: Wazzup, my nerdizzles?