Take a few minutes and check out GroupIntel Predictions. It's an ongoing experiment "in collaborative intelligence production."
They ask the question: "Can a group of people accurately set the homeland security level, determine the current threat environment, and predict future attacks?" You get to help answer it.
Basically, it is a futures market where you are given "cash" to "invest" in future events. If you are correct, you profit and have more to invest in future postulated events, plus you get to help out in an experiment on "the wisdom of crowds."
Give it a whirl and think of some interesting markets to create while you are at it.