How to create a "guided tour" in Rails app?

I've been using Shepherd.js for the last several months in my Rails apps. I found it handles itself best of all the JavaScript tour libraries in a responsive webapp, as the mobile experience is an important part of our product. Plus, its provided themes were easy to integrate into our existing look-and-feel. (You can install the Shepherd.js rails-assets gem for easier use in the asset pipeline.)

I've since wrapped Shepherd.js into a Rails gem called Abraham to make it easier to configure tour content, track which users have seen each tour, and allow users to skip a tour for now.

Another option is IntroJs http://usablica.github.io/intro.js/, both this and Baldrick's answer are great options.