Faye - dirt simple pub/sub for Rack and Node.js - very cool.

Two way communication in the browser isn’t easy. James Coglan brings aims to change that with Faye:

Faye is an implementation of the Bayeux prototcol, a publish-subscribe messaging protocol designed primarily to allow client-side JavaScript programs to send messages to each other with low latency over HTTP.

Essentially, Bayeux lets applications publish and subscribe to data in named channels, both in the browser and the server: