Showing validation errors inline as the user is filling out the form can lead to a better use experience. Learn how to do this using the Client Side Validations gem. (8 minutes)

The Ancestry gem works like a tree but also allows us to fetch deeply nested messages in a single query. It provides a method to arrange them after fetching. (9 minutes)

Are you testing your JavaScript? Learn how to add specs using Jasmine. This episode also covers jQuery integration with jasmine-jquery. (15 minutes)

Faye is a subscription/publishing server which makes it easy to do push notifications within a Rails app. (13 minutes)

The decent_exposure gem makes it convenient to share controller data with the view through methods instead of instance variables. (9 minutes)

With the jQuery Tokeninput plugin it is easy to add an autocompleting list of entries for a many-to-many association. (11 minutes)

Request specs in RSpec are a great way to ensure the entire application stack is working properly. Here I also show how to use capybara with integrated JavaScript testing using Selenium. (13 minutes)

Internationalization is easy to add in Rails, but the YAML files can be difficult to manage. In this episode I show how to use Redis for managing the translations through a web interface. (11 minutes)

Undo and redo behavior is easy to add with a versioning gem such as Paper Trail. Learn how to add an undo link to any model's flash message. (13 minutes)

If you need pagination in Rails 3 try out Kaminari. It is a clean, flexible solution which uses scopes to flow nicely with Active Record queries. Did I mention it also works with Mongoid? (8 minutes)