All of the money raised in the auctions is going to support St. Jude Children's Research Hospital. All in all, about 2,000 server blades will be auctioned off, and you can even aim to buy one from a specific realm -- the hardware where your very own characters once resided! Each blade will be mounted in a windowed case adorned with the WoW logo, and the hardware displayed prominently.
The auctions start on October 17 (just a few days before BlizzCon), with sales occurring in four different rounds. Good luck!