Today I learned about two interesting "predictors" for the presidential election. Both are just entertainment for mathematicians: neither has any experimental evidence supporting its predictive power.
The first is the types of books being sold in each state: the Election Heat Map as tracked by Amazon.
The other only applies when there is an incumbent running for re-election. How many newspapers endorsed the incumbent during his first campaign but have now switched to the opponent? Mitt Romney is doing well by this measure.
I already knew about Intrade and a few of the many sports related coincidences.
Which other "predictors" do you know about?