Do you like math puzzles? Here's a cool one that dates back at least to the 8th century:

100 bushels of corn are distributed to 100 people such that every man receives 3 bushels, every woman 2 bushels, and every child 1/2 a bushel. How many men, women, and children are there?

There are seven solutions, one of which is 20 men, 0 women, 80 children. Can you find the other six?

If you give up, there's a solution here: 100 Bushels of Corn.