Sheldon: [looking at Tweets about his lecture on Raj's laptop] I'm not familiar with the acronym "KMN".
Leonard: Uh, from the context, we think it means "Kill Me Now".
Sheldon: [unsettled] Well��s'pose everyone's entitled to their own opinion. I think I'll turn in.
[He starts to walk to his bedroom]
Sheldon: [very quickly, looking back at his friends] I didn't want to teach those poopyheads, anyway! [leaves]
Howard: [short pause] FYI, I think that's what Darth Vader said just before he started building the Death Star.

Sheldon: Good news. I finally have a handle on my idea for 3-person chess.
Leonard: That is good news. Bye. [starts to leave]
Sheldon: Do you know how I solved the balanced center combat-area problem? Five words: transitional quadrilateral to triangular tesselation.
Leonard: That��that's brilliant.
Sheldon: It's what I do.

Sheldon: Help me! Come back! Penny!

Sheldon: I must say, Amy, I was very impressed to see that Bernadette got her PhD.
Amy: It's indeed admirable. Although, it is microbiology.
Sheldon: Your doctorate is in neurobiology. I fail to see the distinction.
Amy: I'll make it simple for you. I study the brain, the organ responsible for Beethoven's Fifth Symphony. Bernadette studies yeast, the organism responsible for Michelob Lite.

Sheldon: I won't say that all senior citizens who can't master technology should be publicly flogged, but if we made an example of one or two, it might give the others incentive to try harder.

Sheldon: If only there was a way to force Howard to accept my apology to escape this miasma of guilt!
Penny: You know, sometimes stuff just happens and there's nothing you can do about it. For example, Lisa Peterson hasn't talked to me since the 11th grade because no matter how much you apologize, you can't go back and un-dry-hump someone's boyfriend.

Sheldon: What's going on?
Leonard: Oh, Howard's gonna sleep here tonight. He had a fight with his mother.
Sheldon: Did you offer him a hot beverage?
Leonard: [long pause] No.
Sheldon: Leonard, social protocol states: when a friend is upset, you offer them a hot beverage such as tea.
Howard: Tea does sound nice.
Sheldon: You heard the man, Leonard. [snaps his fingers and gestures to the kitchen]
[Leonard starts to walk to the kitchen]
Sheldon: And while you're at it, I'm upset that we have an unannounced houseguest, so make me cocoa.

Sheldon: Where are you going?
Leonard: I'm having dinner with Priya at Raj's. I think Howard's gonna be there; you wanna join us?
Sheldon: But tonight's Thursday. On Thursdays, everybody comes over here and has pizza, or a reasonable facsimile prepared by someone claiming to be Luigi, but who sounds suspiciously like Jackie Chan.
Leonard: Can we make a one time exception for tonight.
Sheldon: We could. We could also stop using the letter M, but I think that idea is isguided and oronic.
Leonard: Just come with me to Raj's.
Sheldon: I don't want to go to a party.
Leonard: It's not a party; it's the same group of people who hang out here hanging out over there.
Sheldon: I'm sorry, but 5 people eating and chatting is a party.
Leonard: How come it's not a party when we do it over here?
Sheldon: Because we don't throw parties.

Sheldon: Whether you forgive me or not, I want you to have this
[Sheldon pulls a couch cushion out of a large bag]
Howard: You're giving me a couch cushion?
Sheldon: No, the cushion is merely symbolic. I'm giving you my spot on the couch.
[Everyone looks at him in shock]
Howard: [aghast] But... you love that spot!
Sheldon: No, I love my mother. My feelings for my spot are much greater. It is the singular location in space around which revolves my entire universe... And now it's yours.
[Howard is speechless]
Raj: [crying] Oh my God, dude. Now you have to forgive him.

Sheldon: You know I can't keep a secret!
Leonard: You can if you try. Think about it this way: if I were Batman and you were Alfred, you'd keep that secret, right?
Sheldon: Why do you get to be Batman?
Leonard: Because the Batman has the secret.
Sheldon: Alfred has secrets, too!
Leonard: Like what?
Sheldon: Alfred knows that Barbara Gordon is Batgirl. Which I've now just told to Batman! See, I cannot keep a secret!

Zack: You know, I saw this great thing on the Discovery Channel: turns out that if you kill a starfish, it'll just come back to life.
Sheldon: Was the starfish wearing boxer shorts? Because you might have been watching Nickelodeon.
Zack: No. I'm almost sure that it was the Discovery Channel. It was a great show; they also said dolphins might be smarter than people.
Leonard: They might be smarter than some people. [Sheldon and Raj laugh; Penny is disgusted]
Zack: [oblivious] Well, maybe we can do an experiment to find out.
Sheldon: That's easy enough. We'd need a large tank of water, a hoop to jump through, and a bucket of whatever bite-size treats you find tasty.

[After his "breakup" with Amy. Sheldon is replacing her with cats]
Leonard: Okay, fine. Live with cats. Be like my Aunt Nancy. She had dozens of them. And do you know what happened after she died? They ate her.
Sheldon: You don't have to sell me on cats, Leonard. I'm already a fan.

[after Leonard kicked Sheldon out of the app team]
Sheldon: All right, I suppose I'll go put on my bus pants.
Leonard: What the hell are bus pants?
Sheldon: They are pants one wears over one's regular pants when one sits on bus seats that other people have previously sat on. But, perhaps from your lofty heights atop the corporate ladder, you've lost touch with the struggles of the common man.
Leonard: Look, I'm still happy to drive you to work. Nothing's changed in that regard; we're still roommates, we're still friends.
Sheldon: Except you identified me, your best friend, as a gangrenous limb that needed to be severed from the organism and tossed away. A desperate act of a little man with a big Napoleon complex!
Leonard: You know what? Go put on your bus pants.

[Amy is trying to convince Sheldon to go to a university fundraiser he has boycotted]
Amy: And consider this: without you to make the case for the physics department, the task will fall to people like Leonard and Rajesh.
Sheldon: Are you trying to scare me? 'Cause you're succeeding!
Amy: Well, then, prepare to be terrified; if your friends are unconvincing, this year's donation might go to, say, the geology department.
Sheldon: Oh, dear, n- not the dirt people!
Amy: Or worse, it could go to... [leans in dramatically] the liberal arts.
Sheldon: No.
Amy: [nods] Millions of dollars being showered on poets, literary theorists and students of gender studies.
Sheldon: Oh, the humanities!

[Amy knocks on Penny's door, getting ready to spread a false rumor as part of an experiment]
Penny: Oh, hey, Amy. What's up?
Amy: [quickly] Sheldon and I engaged in sexual intercourse. In other news, I'm thinking of starting an herb garden. Mum's the word. Gotta go. [leaves]