Thanks to Michael for this excellent story:
It's been a few years, so I don't have the essay any more, but once I had an essay test where I was given an essay question "Do you think it's right to use native americans as ascots?" (the test meant to say "Mascots"). It was april fools day and I was feeling pretty cheeky, so I wrote a paragraph to the effect of "No, because Native Americans aren't made of cloth and they'd probably be very uncomfortable". I wrote my real answer on the next page, but before I turned it in I showed my fake answer to my teacher. You should have seen him; until I showed him that I actually did answer the question, he was absolutely furious at me. But once he learned it was just a joke, he took it in good stride.
If I remember, I think I got an "A" on that test.