Amy: What took you guys so long?
Leonard: Oh, we were following Howard, but for some reason, he turned off his headlights and went up a one-way street.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

Mary Cooper: So who else is coming to this shindig?
Amy: Oh, well, the usual gang. Penny's family is coming tomorrow.
Sheldon: Yeah, and Leonards mother's already here.
Mary Cooper: Oh. Beverly. How nice.
Amy: You've met her, right?
Mary Cooper: Yes, I have. (reveals her cross necklace)
Sheldon: Mother, she's an atheist, not a vampire.
Mary Cooper: Either way, let's stop and get some garlic.

Alfred Hofstadter: Well, on that note, there are many cultures that have an apocalyptic flood as part of their mythology.
Mary Cooper: I don't have a mythology. I have the unerring Word of God. But that's very interesting.
Alfred Hofstadter: Oh. I, I didn't mean to disparage your faith. Actually, I admire it.
Mary Cooper: Really?
Alfred Hofstadter: Yes. Yes, I'm an agnostic myself. But I have prayed many times to God, to turn my wife into a pillar of salt.
Mary Cooper: Well, He came close. Turned her into a giant block of ice.

Mary Cooper: I've always had a special place in my heart for Leonard. Taking care of my baby all these years.
Sheldon: Excuse me, I take care of him.
Mary Cooper: Sure you do.