Whether it's C# or Java, when it comes to programming, I just can't get enough. One of the major struggles I have is finding enough time for all that I want to do. So where do I go when I want a real quick shot of fun? I like to visit Javabat for a real quick shot of all types of programs. It is a web based playground for those of us that don't have enough time to freshen up on our skills.
Recursion in Java was one of the topics that got me, when I first started ten years (or 12) ago, I went to a programming competition invitational, where the team failed to complete one program. Our team ended up finishing 2nd and had we known recursion (and practiced with it), we would have won the competition. So I go to Javabat and practice this technique when I can for fun, they have simple recursion and more difficult concepts in recursion.