Leonard: It's color-coded. Red means "fix right away". Yellow is "eh, whenever you get a chance." And green is "I could probably learn to live with it."

Sheldon: I remember the song! It's called "Darlin'" by the Beach Boys! Oh, thank goodness! I'm not crazy! I don't have to take a pigeon as my bride!
Leonard: There goes our shot at him living on the roof.

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: 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.

Howard: [Chuckles] Look at that. There's finally a woman in your life you can talk to.

Sheldon: Now, today's episode of 'Fun with Flags' is not fun, but it is important. Flags: You gotta know how to hold 'em, you gotta know how to fold 'em.

Leonard: I missed you.
Penny: You see me all the time. You sure you don't just miss the sex?
Leonard: Well, yeah, the sex with you is pretty great. Have you ever tried it?
Penny: I have. You're not wrong.