This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
They have a competition about once a week and you can try out all the past competitions. I'm hoping to get back into it again myself. It's set up pretty well - they have system tests you can run to test your code so it makes for a great learning experience.