FIN Paper - Bell curve

Much of the way we measure risk relies on probability distribution. For many things in life, and business, this is perfectly valid, but for others it is not. Can you come up with some illustrations of business risk measurement where bell curve type analysis is inappropriate? This will take a little research on the Internet. Why may the bell curve be an inappropriate tool for looking at market risk? Find out what Mandelbrot (The Mis Behvior of Markets) and Taleb (The Black Swan) have to say