Netflix, the DVD rent-through-the-mail service, is hosting a competition to improve their movie suggestion system, with a prize of .... $1,000,000 </dr.evil>.  Netflix provides around 100,000,000 historical ratings from their customers (masked, of course), with which to build a scoring algorithm.  To claim the prize, the algorithm must predict another qualifying data set with an RMSE of less than 0.8563, which is a 10% improvement over Netflix's current RMSE of 0.9474.

Last night, having downloaded and briefly looked at the data, I submitted a very simple solution, which at the time placed me 10th with a RMSE of 1.0004.  I know I can do much better than that, given sufficient time to investigate & build a better algorithm - of course I'm sure others can too.  In the end, it's not really about the prize for me (though it would be nice), but rather the competition - seeing how well I can do relative to others.