Take a look at the polling data from Pollster. It just keeps getting better and better. Click the poll for a larger view. The dots represent different polls that have been compiled and averaged, the results of which represent the tracking lines.
Jeff Merkley Versus Gordon Smith For U.S. Senate:
That last one is really interesting. It's a site where people buy and sell predictions as if they're shares in the stock market. Buy $21.60 worth of McCain today and you'll get $100 if he gets elected, whereas Obama shares are selling for $78.90.