Sheldon: Given how much time you spend engaging in pointless self-abuse, you might consider, just this once, using your genitalia to actually accomplish something.

Sheldon: [answers phone] Hi, Mom, how are you? But, Mom, she keeps sitting in my spot. And she touched my food. Okay, yes, I took her clothes, but she started it. No, that's not fair! Why should I have to apologize? I really don't think this is the kind of thing Jesus concerns himself with. No, you're right. I don't really know what Jesus thinks about. All right! Goodbye. [hangs up] [to Leonard] Did you tell on me?
Leonard: Are you kidding me? I already have 2 strikes

Sheldon: You know what they say. Revenge is a dish best served nude.

Sheldon: I've got to find a way to stop this thing.
Leonard: Buddy, I don't think you can. Once it's out there, it's out there. This thing is like the science equivalent of a sex tape.
Sheldon: Frankly, I'd prefer a sex tape.
Leonard: You don't know what a sex tape is, do you?
Sheldon: No.

Sheldon: Are they making fun of us?
Raj: Yep.
Sheldon: I miss the old days when I couldn't tell.

Leonard: You'll never guess what just happened.
Sheldon: You went out into the hallway, stumbled into an inter-dimensional portal which brought you 5,000 years into the future, which you took advantage of the advanced technology to build a time machine, and now you're back to bring us all with you to the year 7010, where we transported to work at the thinkatorium by telepathically controlled dolphins?
Leonard: No.
Sheldon: Aww.
Leonard: Penny kissed me.
Sheldon: Well, who would ever guess that?

Sheldon: I present to you the Relationship Agreement. A binding covenant that in its 31 pages enumerates, illuminates and codifies the responsibilities of Sheldon Lee Cooper - hereinafter referred to as the "Boyfriend" - and Amy Farrah Fowler - hereinafter referred to as the "Girlfriend.
Amy: That's so romantic!
Sheldon: Mutual indemnification always is.

Sheldon: I'm the guy.
Penny: You're not the guy.
Sheldon: Are you sure? It would explain so much. Your constant presence in my apartment. That baffling dalliance with Leonard just to be near me. The way you call me sweetie all the time.
Penny: I call everyone sweetie.
Sheldon: You tramp.

Sheldon: But evolution is not opinion, it's a fact.
Mary Cooper: And that is your opinion.
Sheldon: [to Leonard, Howard and Raj] I forgive you, let's go home.

Sheldon: A fear of heights is illogical. A fear of falling, on the other hand, is prudent and evolutionary.

Sheldon: If you don't mind, I'd like to stop listening to you and start talking.

Sheldon: I must say, Amy, pretending to have intercourse with you has given me a great deal of satisfaction.

Sheldon: Amy, when I look in your eyes and you're looking back in mine, everything feels not quite normal. Because I feel stronger and weaker at the same time. I feel excited and, at the same time, terrified. The truth is, I don't know what I feel, except I know what kind of man I want to be.
Amy: Sheldon, that was beautiful.
Sheldon: I should hope so, that's from the first Spider-Man movie.
Amy: I'll take it.

Sheldon: I've learned that 1 in 700,000 people die from general anesthesia.
Leonard: But do you realize that means 699,999 people don't die?
Sheldon: I suppose that's true. You're such a glass half full kind of guy. I'm going to miss that.

Sheldon: There there, everything is going to be fine... Sheldon's here!