I finally finished the Ruby Koans. It may sound really stupid but they are amazing for teaching you extra stuff you should probably know about ruby, stuff like inject, lamdas and blocks, message passing, overring method_missing and other really cool "tricks" that let you code Ruby better.
For fun I pushed my finished answers onto github. If you're horribly interested you can see them at: https://github.com/lengarvey/ruby_koans. I've also got the code for this blog up there (although as I state in the readme I'd really recommend most people use something more awesome).