A Rails engine to turn on/off features (Feature flipper).
Rapidly and safely prototyping your rails application
feature flipping for ruby (performant and simple)
Easily jumpstart a new Rails application with a bunch of great features by default
Rails observer (removed from core in Rails 4.0)
Integrate SassC-Ruby with Rails!
Sail is a lightweight Rails engine that brings an admin panel for managing configuration settings on a live Rails app