This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
devlins lab looks like a great site for mobile games. A great site for general game development is gamedev.net. It's not specifically a java site, but there is a wealth of material that can be applied to java easily enough.