I have to give a product demo this morning. Although I hope I don't need to use it today, I'm reminded of a little joke I used to tell back in my consulting days to keep the customer occupied when a problem forced me to do an unexpected restart, reboot or reinstall in the midst of a demonstration:

A chemist, a physicist and a computer scientist were traveling in a car when the engine suddenly puttered out and they were forced to pull over to the side of the road.

"We must be out of fuel", the chemist said, "but I just saw a gas station. I'll walk back and pick some up."

"No, no", said the physicist, "that clearly sounded like a mechanical problem. Let me pop the hood and take a look."

"Wait!", said the computer scientist. "I have an idea. Let's all get out of the car . . . and then get back in."