Buffon's Needle
Also quite interesting (I'm glad I followed the link): Buffon's Needle. * In mathematics , Buffon's needle problem is a question first posed in the 18th century by Georges-Louis Leclerc, Comte de Buffon : Suppose we have a floor made of parallel strips of wood , each the same width, and we drop a needle onto the floor. What is the probability that the needle will lie across a line between two strips? Buffon's needle was the earliest problem in geometric probability to be solved; it can be solved using integral geometry . The solution, in the case where the needle length is not greater than the width of the strips, can be used to design a Monte Carlo method for approximating the number π . * [From Wikipedia: http://en.wikipedia.org/wiki/Buffon%27s_needle ]