http://www.protrade.com
PujolJunkie introduced me to this. You can buy stock in players and teams and watch as they increase or decrease in value. It's all fake money, so it doesn't cost anything. I bought some COLBY (Colby Rasmus), CARDS (the Cardinals team) and AWAIN (Adam Wainright). I'm about $600 ahead right now, poor PJ is thousands in the hole.