I've been doing some work in Prediction Markets for IFTF, and have been particularly interested in the concept of assassination markets: I predict this person will die can be transformed into a price on their head.
The thing that's fascinating is that markets have positivity and negativity built into them all the time. However, with prediction markets, it becomes explicit. A new betting site, BetUs.com, allows people to bet on specific outcomes for global warming.
Will new types of regulation spring up to eliminate the possibility of creating markets in destruction?