Hey! We have an economy tag! Awesome!
Anyways, found this wired article pretty interesting - all about how one quant formula killed the world's economies.
http://www.wired.com/print/techbiz/it/magazine/17-03/wp_quant
It's fascinating - thirty years ago high-level theoretical physicists and mathemeticians were working in the defense industry. Ten years ago? They were working for Bear Stearns, and this formula is something we see in computers all the time - a perfectly elegant but buggy bit of code that then gets misused by people who don't understand how it works a million times until everything crashes around them.