The problem is that currently the closest thing to a prediction market is Bets of Bitcoin, and they use probably the bizarrest set of rules you have ever had the misfortune to lay eyes on. So.. not really an alternative at all except for the most wildly mispriced bets on it (where you can be sure to come out with a profit regardless of how much the rules screw you).
I see the wiki lists 2 other prediction markets, but they seem to handle sports only.
Prediction markets don't necessarily have to be real currency and it's a misconception that they are only accurate if you're using real money. We have run a prediction market using fantasy currency for years: http://home.inklingmarkets.com. We also run run private markets for companies...
Of course they don't have to use real money. But if you're happy with playmoney, nothing stops you from, say, just writing down predictions and checking how they ultimately do. (I do just this; great practice and useful in many ways.)
However, we shouldn't forget that many people aren't going to contribute their time and expertise without a concrete reward. Nor do I blame them.
You don't specify when you are sampling the market. It often wouldn't be surprising, or useful, that a market correctly predicts an event the day before it occurs.
I see the wiki lists 2 other prediction markets, but they seem to handle sports only.