I have just finished reading the free online book Getting Started with Grails. Grails is a "Ruby on Rails" competitor that uses the Groovy scripting language. Grails follows the convention over configuration approach to application development and it seems to do a fantastic job. The advantage of using Groovy over Ruby is that Groovy srun in the Java VM and so you have access to the best of class tools available in Java.
I have not yet experimented with Grails and so I do not know how much practice differs from preaching. I have a small project based on Galley that I would like to use to test out alternative frameworks. I had intended to build this first with Rails but I think I will use Grails instead.