Leonard: I wonder if that's why I have such a dysfunctional relationship with Sheldon. I had a dream the other night that I was in a cave, and I was nursing a baby. But the baby had Sheldon's head on it.
Mandy: And your wife is worried about me?

Leonard: Some kind of nerd? I'm the king of nerds.
Penny: What does that mean?
Leonard: It means that if someone makes me mad, I won't help them set up their printer.

Leonard: How about that, Einstein was wrong.
Penny: What?
Leonard: Approaching the speed of light doesn't slow down time, approaching them does.

Sheldon: What self-important preening fraud are they honoring this year?
Leonard: I'm so glad you asked it like that. You!

Leonard: I bet I could throw a rock in this room and come up with three better friends!

Leonard: *Doing Mr. T impression while holding a action figure of Spock with Mr. T's head* I pity the fool who's illogical!

Sheldon: Boy, do I have to urinate.
Leonard: If only there were a solution to that.

Leonard: Star Wars on Blu-ray.
Penny: Haven't you seen that movie like a thousand times?
Leonard: Not on Blu-ray. Only twice on Blu-ray.
Penny: Oh, Leonard.
Leonard: I know, it's high resolution sadness.

Leonard: Remember the day we first met and you asked me to go to your boyfriend's apartment to get your TV back? And he was 9 feet tall and he took my pants off and you said- What was that? What did you say? Oh, yes, you said you owed me one.
Penny: Oh, come on, that's not fair.
Leonard: I came home with no pants.

Sheldon: I couldn't sleep knowing that just outside my bedroom is our living room and just outside our living room is that hallway and immediately adjacent to that hallway is [Penny's messed up apartment]!
Leonard: Do you realize if Penny wakes up there's no reasonable explanation to why we are here?
Sheldon: I just gave you a reasonable explanation.
Leonard: No, no. You gave me an explanation. Its reasonableness will be determined by a jury of your peers.

Leonard: Merry Newtonmas everyone.

Howard: Why would the military want Sheldon?
Leonard: I don't know. Target practice?

Leonard: We're always the good guys. In D&D, we're lawful good. In City of Heroes, we're the heroes. In Grand Theft Auto, we pay the prostitutes promptly and never hit them with a bat.
Sheldon: Those women are prostitutes? You said they were raising money for stem cell research.

Leonard: I'm fine. How are you?
Beverly Hofstadter: Menopausal.
Leonard: Now I'm less fine.

Leonard: There's chapters about potty training, bed wetting and masturbation. Basically, if something came out of me, she wrote about it!