Pragprog-depot-prg is a project mainly written in Ruby, it's free.
Depot example application from the Pragmatic Programmers adapted to use post-redirect-get page flows.
This project contains the depot application as described in the Agile Development with Rails book from the Pragmatic Programmers.
Departures from the book:
All model objects use a UUID as their primary key, rather than the standard Rails autogenerated numeric key.
Uses HAML and SASS for HTML & CSS generation.
The user, product and store controllers have been modified to use the POST-REDIRECT-GET web application design pattern as an exercise to see what it takes to make active-resource controllers (and other rails controllers) behave nicely with browsers' back & refresh buttons.
Uses RSpec and Cucumber for testing.