git clone git://github.com/rspec/rspec-dev.git
cd rspec-dev
gem install bundler
bundle install
rake
To setup your development environment run rake. This will pull all of the
rspec repos, build and install the gems, and then run the default rake task
in each, which will run their specs.
After the initial clone you can run rake git:pull to update to the latest bits.
Run rake -T to see the available tasks for dev mode.