Simple 'database cleaner' approach using `config.around`. Was able to cut down some seconds out of the suite. Thanks to @brandonhilkert

spec_helper.rb

RSpec.configure do |config|
  config.around do |example|
    # For examples using capybara-webkit for example.
    # Remove this if you don't use it or anything similar
    if example.metadata[:js]
      example.run

      ActiveRecord::Base.connection.execute("TRUNCATE #{ActiveRecord::Base.connection.tables.join(',')} RESTART IDENTITY")
    else
      ActiveRecord::Base.transaction do
        example.run
        raise ActiveRecord::Rollback
      end
    end
  end
end

I saw a dramatic improvement in the test suite I'm working with... When I mean dramatic, I mean 8 minutes to 27 seconds...

I'm running jruby 1.7.4 (1.9.3p392) 2013-05-16 2390d3b on Java HotSpot(TM) 64-Bit Server VM 1.6.0_51-b11-457-11M4509 [darwin-x86_64]