Penny: Leonard, I didn't know you played the cello?
Leonard: Yeah, my parents felt that naming me Leonard and putting me in advanced placement classes wasn't getting me beaten up enough.

Leslie: I admire your fingering.
Leonard: Thank you.
Leslie: Maybe some time you can try that on my instrument.

Leonard: What about the really long hug? What did that mean?
Penny: That wasn't a long hug.
Leonard: It was at least five Mississippis. A standard hug is two Mississippis tops.

Sheldon: I'm a theoretical physicist, a career I chose in no small part because it's indoors. But if I'm able to detect slow-moving magnetic monopoles there, I will be the first scientist to confirm string theory. People will write books about me. Third-graders will create macaroni-art dioramas depicting scenes from my life.
Leonard: Sure, maybe a tableau of me trying to pummel you to death.

Penny: Okay, what just happened?
Leonard: I don't know. Between you playing chess like Bobby Fischer and Sheldon being okay with you in his spot, I'm guessing someone went back in time, stepped on a bug, and changed the course of human events.

Stephanie: I just performed a Sheldonectomy.
Leonard: Careful, if you don't get it all, it'll only come back worse.

Leonard: To Mrs. Wolowitz. A loving mother. To all of us. We'll miss you.

Leonard: The place really looks great.
Raj: Yeah, you should have burnt it down years ago.
Stuart: I keep telling you, I didn't burn it down.
Leonard: We know. We know. Because burning something down for the insurance money is a crime. *wink*

Leonard: Why don't we go get the food for the party?
Stuart: Thank you.
Raj: Smart. Looks like we're being helpful.
Leonard: When really we're just exiting an uncomfortable situation. *fist bumps with Raj*

Penny: Wait, wait, just to be clear, when you guys say spa, does that mean the same thing as when regular people say it?
Leonard: Pretty much. Except we keep our shirts on in the sauna.

Leonard: I'm still not adjusted to how the SyFy channel spells their name now. S-Y-F-Y, that's siffy.

Leonard: Hey, I am a young man in his sexual prime. Under the right conditions, I am capable of just, really crazy stuff.
Penny: Really? What is the craziest thing you've ever done with a woman? And the time you and I had sex in the ocean does not count.
Leonard: Come on, that's got to count. There was a really strong undertow. We could have died.

Leonard: Whoa, it's a little early to start dropping J-bombs, don't you think?

Leonard: I never wanted to play the cello. How do you meet girls playing the cello? Hey, you want to come over to my house and listen to me play an instrument that sounds like a suicidal bumblebee?

Howard: Maybe me and Bernadette aren't right for each other.
Leonard: Look, Howard, I'd say there's a lot of fish in the sea, but I watched you dangle your hook in the water for years. Do not throw her back.