Sheldon: (Yelling at a mockingbird) And you, the notes are C, D, E, G and A! You pick one or I'm chopping down that tree!

Sheldon: Okay, stop ruining Valentine's day and order my pizza.

Penny: Leonard's had girls over before, right?
Sheldon: Oh, yes, but there's usually planning, courtship and advance notice. Last time I was able to book a cruise to the Arctic to see a solar eclipse.
Penny: Wait, you had to leave the state because your roommate was having sex?
Sheldon: I didn't have to, the dates just happened to coincide.

Sheldon: Do you like trains?
Priya: Not particularly.
Sheldon: You might as well just wait at the airport for your flight.

Howard: How'd you get him to come to your house?
Sheldon: As Professor Proton always says, there is no problem you can't solve if you use your noggin.
Leonard: And he wrote him a check.
Sheldon: Yeah, that too. A big check.

Sheldon: Would you like some advice?
Leonard: Sure, why not?
Sheldon: Then this is the perfect time to launch a blog with an interactive comments section.
Leonard: Gee, thanks a lot.

Penny: Ooh, I thought I smelled pizza.
Sheldon: That's remarkable. If pepperoni were an explosive substance, you could replace German shepherds at our nation's airports.

Amy: (To sheldon) Hey, cuddles.
Leonard: Cuddles?
Sheldon: Yes, "cuddles". We cuddled. Grow up, Leonard.

Sheldon: Oh really, Leonard? Are you going to have another one of your hissy fits?
Leonard: Hissy fits? I have hissy fits?
Sheldon: Yes, and I have a theory why. Because of your lactose intolerance, you switched over to soy milk. Soy contains estrogen-mimicking compounds. I think your morning Cocoa Puffs are turning you into a hysterical woman.

Sheldon: They can't just cancel a show like Alpha, you know. They have to help the viewers let go. Firefly did a movie to wrap things up. Buffy the Vampire Slayer continued on as a comic book. Heroes gradually lowered the quality season by season 'til we were grateful it ended.

Sheldon: I was actually trapped by Penny and forced into reveleaing confidential information about Howard's father.
Leonard: What information?
Sheldon: I can't tell you, I'm bound by closet organizer-organizee confidentiality.
Raj: Just tell us.
Sheldon: Badgering me won't work. What would work is saying Penny would tell us anyway.
Leonard: Then that.
Sheldon: Very well. Everyone's on their game today.

Leonard: Really? You're going to risk getting sleepy in the middle of your themodynamic fluctuations seminar? You know what happens when you yawn in public.
Sheldon: Everyone will see my oddly shaped uvula.

Penny: The letter was found in Bernadette's closet. Doesn't that count for something?
Sheldon: Are you pointing out that California is a community property state and since Howard and Bernadette are married the intellectual property contained in that letter is jointly owned by the two spouses?
Penny: Yeah, obviously.
Sheldon: Well played. Sometimes I don't give you enough credit, Penny.

Sheldon: Really? The only time I'm ever picked first for a team and I'm stuck with the liability?

Penny: This isn't fair to you, Leonard. I'm sorry. *runs off*
Sheldon: Penny, wait, come back. I'll get you ice cream!