Here is a riddle:

A farmer has three young men working for him as farm hands, and he knows they all want to fuck his very hot 19-year-old daughter. Rather than fighting nature he decides to hold a contest. He tells all three to line up so that the third is looking at the back of the second, the second is looking at the back of the first, and the first, facing in the same direction as the second and third, is looking at the scenery. The farmer tell the men that he will put a top hat on each of their heads. He has three black ones and two white ones, but he will place only one hat on each of their heads. Then he tell them that the man who figures out which color hat is on his own head without looking at his own hat or, in the case of the first and second man, turning around to see what the other(s) is/are wearing, will get to have their way with his very ready daughter. He ask the third man what color hat he thought he was wearing and the man answered that he did not know. He ask the second man and he too said he did not know. He asked the first man and he said he did know. So, what color hat was the first man wearing and how did he know?