Leonard: Great. What do you want to do?
Sheldon: I don't know. What do you want to do?
Penny: I don't know. What do you want to do?
Leonard: I'm starting to remember the problem with Anything Can Happen Thursdays.

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: 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.

Professor Proton: Can I ask you a question?
Leonard: Yeah, sure.
Professor Proton: Why do you put up with Sheldon?
Leonard: Oh, you know because we're friends.
Professor Proton: Why?
Leonard: Wow, you ask really hard questions. Look, I know he can be aggravating, but what you have to remember is he's not doing it on purpose, it's just how he is. But he's also loyal and trustworthy and we have fun together.
Professor Proton: You know you're describing a dog?
Leonard: He did bite me once. But in his defense, I came up behind him while he was eating.
Professor Proton: They hate that.
Leonard: Sheldon is the smartest person I have met. He's a little broken and he needs me. And I guess I need him too.
Professor Proton: Why is that?
Leonard: Boy, you will not let this go, will you?

Penny: Sheldon, what did we say about being a nicer friend?
Leonard: Thank you.
Penny: Leonard, what did we say about being a gullible weeny?

Raj: Hey, listen to this. Murder, cannibalism and satanic rituals are just a few of the thousand-plus horrors that await.
Howard: I just helped my mum out of the tub, so I'm one slippery horror ahead of you.

Raj: You know when Cinnamon won't take her medicine. I hide it in a piece of cheese.
Howard: Good idea. We can wrap up the pill in cheese, feed it to Cinnamon and then my mom can eat Cinnamon.