This podcast is an excellent example of how collective human psychology can take down the global financial system. From a school lunch room we hear an eerily similar story to that of Tulipomania; widely considered the first economic bubble in 1637 when a single tulip bulb sold for +10x the annual income of a skilled craftsman.
http://www.npr.org/blogs/money/2009/03/hear_delicious_cake_futures.html