This is a walkthrough of getting Rails 3 up and running with RSpec and Cucumber. Rails 3 and Rails 2 don’t play nicely together, so I recommend you use RVM to create a separate gemset for Rails 3. (I did all this under Ruby 1.9.1 just for fun. YMMV.) To install the latest rails pre-release (Rails 3 beta 3 at the time of this writing): gem install rails --pre It’s got a lot of dependencies nowadays