Sage lets you build rich, highly functional, cross platform web-enabled desktop applications and applets by simply marking up the UI and attaching JavaScript (or Ruby, Python, etc.) event handlers. You simply point sage to a URL and it downloads the markup and accompanying scripts and renders the application or applet in real-time (the same way a browser renders documents). All that is required to run Sage is a Java Virtual Machine (v1.5 or later, v1.6 preferred).