NemeStats

NemeStats (as in "Nemesis Statistics") is a free web application for logging games played among a relatively stable group of players. It takes only a moment and will give you statistics on your win percentage, average rank in games, who is your Nemesis and who is your Minion, etc. When you register, a new "Gaming Group" will be created where you and other players in your group can watch your statistics materialize over time.