The Farmer
A farmer needed to take a fox, a chicken, and a bag of corn across a deep, wide river. To get across the river, he only had an old canoe which could carry himself and only one of his charges at a time. Since he could only carry one across at a time, he had to be very careful about about the order in which he transported the fox, the chicken, and the corn. If he left the fox alone with the chicken, the fox would eat the chicken. If he left the chicken alone with the corn, the chicken would eat the corn.
After thinking about it for a while, the farmer figured out how to get all three across the river safely. How did he do it?
(they don't get any easier than this)