We've laid down the basic architecture for the Ruby IDK 5.3 and written most of IPortletContext and IPortletRequest. We also now have a test bed application built in Rails, the output of which checks for CSP-Gateway-Type == 'Plumtree', displays your HTTP environment (dumps all the headers) and then proceeds to call each IDK method in IPortletRequest.
This is our first adventure in Ruby and I must say, it's easy breezy. What a great language! And don't get me started on how easy it is to prototype a web application with Rails using scaffolding. Makes J2EE seem almost neolithic.