Use CarouFredSel with Rails. It's pretty good!

Gemfile:

gem 'caroufredsel-rails', :git => 'git://github.com/johnbintz/caroufredsel-rails.git'

app/assets/javascripts/application.js:

//= require caroufredsel

carousel = new Carousel(
  $('#carousel_items'),
  {
    onChange: function(items) {
      // something when the items change
    },
    otherCarouFredSelOptions: 'go here'_
  }
);

Carousel objects respond to the following:

• slideTo(index): Slide to the target original index
• moveTo(index): Immediately move to the target original index
• pause: Pause the carousel

Get at the original carousel with Carousel#carousel

Needs CoffeeScript, 'cause I'm lazy right now!