I'm going to write a brief primer on the basic .NET techs, what they are, what they do, etc. Something where I spend maybe 3 - 5 sentences per item. I'd love to see something similar for the Ruby ecosystem (for example, "YAML", "Rails", "Rubinius", etc.).

That makes sense about not wanting to use JRuby until you wanted to do Android. The JRuby ecosystem is only appealing to me because it allows Ruby to be run in places it normally would not go. The Java libraries and interaction with the OS are not appealing to me. There's some useful stuff in there, don't get me wrong, and I feel like Sun's inability to do anything useful made the open source community around Java much more active than .NET's. But for the most part, the .NET world just watches Java (and Ruby, for that matter) and copies anything truly useful (ASP.NET MVC and NHibernate are two great examples of .NET cherry picking ideas from other systems) while leaving the less useful stuff aside.

It's too true about Java & licensing issues. I tried a Java-based CMS on my FreeBSD machine ages ago... what a nightmare it was. Never mind the fact that I've always thought that Tomcat felt like a helpless kludge (my opinion of Apache dropped a lot due to Tomcat), just getting the JVM itself installed and running was a truly mindbending experience due to the licensing. I was utterly baffled by the decision making process that went into it.

J.Ja