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).
Raphaël is a small JavaScript library that should simplify your work with vector graphics on the web. If you want to create your own specific chart or image crop and rotate widget, for example, you can achieve it simply and easily with this library.
Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.