This guy didn't get a chance to study for one of his finals. So at the test he knew he'd be toast even if he attempted to answer any of the questions. So this is what he did: he got 2 exam booklets. He put one booklet in his jacket. In the other he sat down and during the entire test wrote a letter to his mother:
"Dear Mom,
I'm sitting at the final exam. I've finished early, and they won't let me out of here, so I'm taking some time to write you a letter...."
After the exam, he handed in the letter to his mom, and took the empty booklet home. At home he quickly looked up all the answers and filled in his empty booklet with all the right answers. He then sent his test to his mom. Sometime later the prof called him up and the following discussion took place:
"In the exam collection, I found a letter to your mother instead of your exam answers. Do you have an explanation?"
"Oh, I must have mixed up the two booklets. I must have sent my mom the exam answers. I'll get her to send that exam booklet to you right away."
The prof got the exam booklet, the student got the A!