I would like to test my ranking system based on information theory. I need a database of games with outcomes and ranks of the single players. Where can I find this?
There was a Kaggle competition sponsored by the FIDE looking for an alternative to the current ELO system. The link is:
The dataset has over a million actual games covering ~50k players. There's also discussions of the alternative approaches used (the competition itself is now over) and scoreboard of metrics to see how well your ranking system compares.
There is actually a rather large DB of chess games at http://chesstempo.com. I'm not sure how open they are with it, but it could be a good starting point.