Orange County Ruby Users Group

I was on digg.com and found this link that does a side-by-side comparison of a program written in Ruby, Java, C++ and Python. Interesting way to compare the languages. I remember when I was first learning C# way back the book “C# for Java developers” was a great way to quickly get up to speed with C# because of it’s similarities to Java. Anybody know of any sites or books that teaches Ruby by comparing it to another language?