Faye is an easy-to-use publish-subscribe messaging system based on the Bayeux protocol. It provides message servers for Node.js and Rack, and clients for use in Node and Ruby programs and in the browser.

James Coglan

This is a simpler, open source equivalent to systems like New Bamboo's Pusher, but using the Comet-like Bayeux protocol with AJAX rather than WebSockets. Start a server (based on node.js or Ruby/Rack) and then push and pull messages between clients and apps in JavaScript and Ruby.