Cloud9

Cloud9 is an open source IDE built with Node.JS on the back-end and JavaScript/HTML5 on the client. It is very actively maintained by about 15 developers in both Amsterdam and San Francisco and is one component of the hosted service at c9.io. The version available here runs on your local system. Cloud9 balances the power of traditional desktop IDEs with the simplicity and elegance of editors like TextMate and Subl