If you’re a big World of Warcraft addict, then I might point you to this page. You’ll likely need to log into your account to access it, however, doing so will put your name into the pool for a Wrath of the Lich King beta key.
The beta selection is completely random, so there’s nothing that you can do to better your chances (unless you have more than one paying account). Also, if you happen to be one of the lucky bastards that gets their name pulled out, you are welcome to give it to a friend or relative.
Yes, this means you can also likely sell it for a small fortune on eBay. However, doing so may very well win you the award for World’s Biggest Douche.