I am familiar with Ruby on Rails. I think that is the best Framework for Web Development. Yesterday I installed JRuby. That is the Ruby language implemented in Java. It is pretty good. Here is the Homepage:
http://www.jruby.org
On the Download Page there is a bundle for Mac OS X, too.
http://www.jruby.org/download
The installation worked pretty smooth. After the installation you can use in the command line like that:
jruby -S --version
You can install the rails framework like that.
jruby -S gem install rails
and create a new project like that
jruby -S rails new blog
It works pretty good. And with JRuby you can directly access Java classes. You can import JAR files and take advantage of the whole Java world.
Robert Reiz 