Sheldon: I never joke about safety.

Sheldon: Will you Boozehounds stop that infernal clinking? And the Answer was Elephant.

Sheldon: If you want to blend in with Penny's friends, I'd think looking like an idiot would be the perfect camouflage.

Penny: No, I can't. Sheldon, honey, I don't want things to be weird between us.
Sheldon: Won't it also be 'weird' if I have to say hello to you every morning on my way to work and you're living in a refrigerator box and washing your hair with rainwater?

Sheldon: Howard, I have to go to the bathroom and no one will take me home.
Howard: What's wrong with the bathroom here?
Sheldon: Pneumococcus, streptococcus, staphylococcus and other assorted cocusses.
Howard: Sheldon, my mother is on her deathbed and my fiance is grief-stricken over putting her there. I'm NOT taking you home!
Sheldon: Will you at least go with me to the restroom here so you can open the door and flush the urinal?
Howard: No!
Sheldon: This might be a good time to point out, Howard, that friendship requires a certain give and take.

Sheldon: 'He drank from Leonard`s glass' - the words they will be carving into my tombstone.

Howard: There must be another way.
Raj: You could try calling AAA. But based on NASA's latest timetable, they wouldn't be out there for another 35 years.
Sheldon: Plus, I understand you need to be standing next to the vehicle with your card when they arrive.

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

Sheldon: There's no need to interact with me. I'm just here to observe.

Sheldon: As a mental exercise, I invite you to figure out why the two of us can't play three-person chess.

Sheldon: It's hard to say no to Yoo-hoo. The name literally beckons.

Sheldon: According to the Roommate Agreement, Paragraph 9, Subsection B: The right to bathroom privacy is suspended in the event of force majeure, and believe me, I am experiencing a very majeure force.

Sheldon: Give us the precious!

Sheldon: "Barney Bunny has two daddies now." Probably something about homosexual rabbits.

Penny: I'm running really late (to work).
Sheldon: Then I have a simple solution: Go up to the roof, hop over to next building, there's a small gap, don't look if you suffer of vertigo, and use their stairwell.
Penny: You are joking, right?
Sheldon: Oh, I never joke when it comes to vertigo.