JustGage is a handy JavaScript plugin for generating and animating nice & clean dashboard gauges. It is based on Raphaël library for vector drawing.

Checkout http://justgage.com for details, demos, current release and more.

In your Gemfile, add:

gem 'justgage-rails'

Add the following to your application.js:

//= require raphael
//= require justgage

JustGage by Bojan Djuricic

Rails gem modeled after raphael-rails by Cameron Prebble