I'm giving away a free copy of my iPhone app, Zinger, to every person who gets their app running with our new metrics service, Dash. Just email me. Steps (documented in more depth here):

1) Request an invite by signing up at https://dash.fiveruns.com
2) Log into Dash, create a new Rails application and note your application token.
3) Install the gem:

sudo gem install json
sudo gem install fiveruns-dash-rails -s http://gems.github.com

4) Add the gem to your config/environment.rb

Rails::Initializer.run do |config|
  config.gem 'json' # needed because of a bug in json_pure
  config.gem 'fiveruns-dash-rails',
             :lib => 'fiveruns_dash_rails',
             :source => 'http://gems.github.com'

5) Add the initializer file config/initializers/dash.rb to start Dash:

if defined?(Fiveruns::Dash)
  Fiveruns::Dash::Rails.start(:production => 'YOUR-APP-TOKEN-HERE')

This will start Dash in the production environment. We don't recommend using Dash in development mode. If you have a staging environment, you can create a separate app for that environment and combine the two like so:

if defined?(Fiveruns::Dash)
  Fiveruns::Dash::Rails.start(:production => 'PROD-TOKEN', :staging => 'STAGE-TOKEN')

Email me if you have problems -- I'm happy to help people give Dash a test drive. Dash is 100% free right now until we've worked out pricing models but rest assured there will always be a free tier so you don't have to worry about your app costing you money in the future. I hope your Dash test drive is full of rimshots with no sad trombones!