Sheldon: Come on, Leonard, if you roll a six, Penny dies horribly in a nuclear meltdown. See what I mean when I say the fun is real?

Sheldon: There are more things in Heaven and Earth, Horatio, than are dreamt of in your philosophy.

Leonard: Look at that. To my friend, Leonard, from Stan Lee, Excelsior!
Howard: Awesome. Mine says, "To my friend, Howard, from Stan Lee, Excelsior!"
Raj: Mine says, "To Raj, from Stan Lee."
Howard: That's 'cause you pissed him off about his character names.
Raj: Hey, I didn't even mention Dum Dum Dugan, or Green Goblin, Matt Murdock, Pepper Potts, Victor von Doom. Oh, and worst of all, Millie the Model.

Sheldon: Cathedra mea, regulae meae. That's Latin for my chair, my rules.

Raj: Oh, my goodness, look at this room! Champagne! Roses! Oh and little chocolates! This is going to be the best Valentine's Day ever.
Leonard: Yeah, I forgot about all this.
Raj: But I never will.

Sheldon: Oh, good, you're home. I need you to do me a favor.
Leonard: Sure.
Sheldon: Go apologize to Penny.
Leonard: What?
Sheldon: Right now would be good.
Penny: (knocking) Leonard!
Sheldon: Although, a few minutes ago would have been better.

Leonard: Not only did Sheldon save my life, he didn't rat me out to the landlord. Or the police. Or Homeland Security.
Penny: Okay, so, basically, you're the reason I have to walk up and down three flights of stairs every day?