Cramp is a fully asynchronous realtime web application framework in Ruby. It is built on top of EventMachine and primarily designed for working with larger number of open connections and providing full-duplex bi-directional communication.

Add this line to your application's Gemfile:

gem 'cramp'

And then execute:

$ bundle

Manual installation:

$ gem install cramp

Please check out http://cramp.in to find out more.