Perhaps some levity?

It seems that a university Philosophy professor made a great breakthrough and had agreed to do a series of talks at universities throughout the country detailing his discoveries. Because the professor disliked airplanes, he hired a chaffeur to drive him from one spot to the next. Spending so much time together, the professor and the chaffeur became friendly and in the course of time, the chaffeur confided that he thought the professor had about the easiest job in the world.

"How's that?" asked the professor.

"Well," said the driver. "You give the same talk night after night. You get asked the same questions night after night. There's just nothing to it. Really, I've heard it so many times now, even I could do it."

At this, the professor challenged the chaffeur and at their next stop, the chaffeur and the professor changed roles (and clothes). Good as his word, the chaffeur gave a very successful talk and, just as he had predicted, the same questions were asked. That is, until one person asked a new question, one the chaffeur-cum-professor didn't know. He thought about it for a while and finally said, "Young man, that is the single most stupid question I have EVER been asked. Why, I'm surprised that you don't know the answer to it. I would think anyone would. In fact, the question is so simple, I'm going to have my chaffeur answer it!"

--

This same professor comes into a class on Philosophy on the last day of the term and tells the students that 100% of their grade for the class will be based on the paper he is about to ask them to write. He pulls up a chair, sits down, and declares: "You have 1 and a half hours to prove to me, using the things you've learned this term, that this chair does not exist."

All of the students save one begin frantically scribbling, tying Bhuddism to Fruedianism to Aristotle. The last student looks very carefully at the professor for about 30 seconds, then writes a few words on a piece of paper, hands it in, and leaves. When the grades are published, the entire class is mystified to see that only the one student passed. His paper is posted next to the grades, and says simply:

"What chair?"