Backbone.js 1.0.0 Underscore.js 1.5.0
Add the following to your Gemfile:
gem "backbonejs-rails", "~> 1.0.1"
Then use Bundler to install:
$ bundle install
$ rails g backbonejs:install
Optionally you can add -ich to the end of that command to have icanhaz.js included.
What Does it do?
backbonejs-rails adds the necessary libraries to your Rails app for using Backbone.js.
For templates you can optionally include ICanHaz.js
$ rails g backbonejs:install -ich
Outdated Screencast? Yep I have one.
You can find my screencast on Backbone.js and Rails 3 here