JRuby

Information on JRuby.

ActiveRecord JDBC - JDBC-backed adapter for ActiveRecord.
appengine-jruby - run Ruby code on Google App Engine including the option of using Sinatra, DataMapper and eventually Rails 3.
Headius - blog of JRuby’s top contributor and evangelist, Charles Nutter.
Jemini - game library designed to allow creation of reusable features.
JRuby@Gemcutter - list of available JRuby gems from Gemcutter.org.
JRuby@Github - JRuby source.
JRuby.org - official JRuby site.
JRuby-Rack - a lightweight adapter for the Java servlet environment that allows any Rack-based application to run unmodified in a Java servlet container.
Rawr - a packaging and deployment tool, is all you’ll ever need for your JRuby projects.
Warbler - a gem that makes a .war file out of a Rails, Merb, or Rack-based application.