Leonard: Okay, now, what you want to do first is turn on the ignition and shift into drive.
Sheldon: I haven't fastened my seat belt yet.
Leonard: Okay, fasten your seat belt.
Sheldon: Click. Now, are there air bags?
Leonard: You don't need air bags.
Sheldon: What if a simulated van rear-ends me?
Penny: I'll hit you in the face with a pillow.