Launched back before NFL week 1. But, that was DjangoCon 2011, so the post happens today.
Best Buy's site is operating for the third year in a row. Originally it was open to the public, but now it is employee only. You play by selecting a line-up every week and play against your co-workers and against the CEO. Makes for really fun team building.
It uses a fantasy games framework originally developed by Rudy Menendez and myself back in 2008 for Grupo RBS's first fantasy football game ever. It's evolved quite a bit over 3 years and it's now a mature fantasy games framework that can easily handle over 1000 sign-ups an hour before you need to start rain dances for your cloud server.