Altlaw-jruby is a project mainly written in ..., it's free.
Custom JRuby build for AltLaw.org
altlaw-jruby: Custom build of JRuby for AltLaw
AltLaw requires JRuby to be packaged as one complete JAR, including several Rubygem libraries. This Maven/Ant installation script builds a development version of JRuby with all the necessary gems pre-installed and correctly packaged in the JAR.
To install it, simply run "mvn install".
This source code repository contains code used to develop AltLaw.org, a free legal research web site.
More information is available at http://www.altlaw.org/ and http://lawcommons.org/