I just got a skeletal Ruby on Rails application running on a Java Virtual Machine using JRuby:
—This is running on Windows XP which is running in a Parallels VM which is running on my Mac. To recap: it’s Ruby on Java on Windows on Mac OS X. Who could have predicted that a few years ago! Next steps: hook up a database and try to deploy a Rails application to a servlet engine. I think this could be very useful in future!