Node.js-demo is a project mainly written in JavaScript, it's free.
Demo code sending real time events to the browser.
This is the source code related to that post: http://www.no-margin-for-errors.com/blog/2010/07/26/deliver-real-time-information-to-your-users-using-node-js/
This code is released under an MIT license. Feel free to re-use or build upon it.