Though not noted on the U.S. site, the European Diablo III Page has word on a Diablo III beta key giveaway on the Diablo Facebook Page (thanks Gamer's Hell). Here's word:

Whoa, we're halfway there! If you’re still praying for a Diablo III beta key, take heart. We've gone through half of the keys we're giving out on Facebook, but the glass is still half full, so be sure to sign up for the sweepstakes if you haven’t already. Every Monday, we're picking 200 lucky entrants to receive a key, and every fourth person will hit the jackpot and receive an additional key to give to a friend. Give it a shot!

If you haven't entered yet, you can do so at the Diablo III Beta Key Sweepstakes page.