"A lightweight clean implementation of the Bayeux (COMET) protocol as a jQuery plugin, with a test server in Sinatra (uses async_sinatra under Thin)."

"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."

"Pusher is a Rack middleware that implement Ajax Push aka Comet" - a juggernaut alternative?