Rebecca: I could give you some free sessions.
Penny: Oh, is that offer for everybody?
Leonard: (chuckles) Nice try. I'm not going.

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.

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.

Leonard: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Sheldon: Who's ready to laugh? [Leonard groans] Okay. So Feynman, Einstein and Schrodinger walk into a bar. Feynman says, "It appears we're inside a joke." Einstein replies, "But only to an observer who saw us walk in simultaneously." To which Schrodinger says, "If someone's looking in the window, I'm leaving."
Leonard: [chuckles] That's actually funny.
Raj: You should send that to Jimmy Fallon.

Raj: Sheldon, what did Amy have that attracted you?
Sheldon: Oh, so many things. Her mind, her kindness, and especially her body.
Raj: Really?
Amy: Relax. We're the same blood type. He knew he could harvest an organ.

Penny: So, Bert, you were telling us how you updated your profile?
Bert: Right. I wasn't getting any responses, and then I added, "Recent $625,000 MacArthur grant winner", and five minutes later, I met my soul mate.
*Amy goes to the hallway*
Amy: I was wrong. You can come back in.