TypeScript was released by Microsoft just over a week ago and is being touted as "a language for application-scale JavaScript development."
The basic premise is JavaScript with optional static typing, allowing superior tooling support.
* TypeScript is a typed superset of JavaScript that compiles to plain JavaScript.
* Any browser. Any host. Any OS.
* Open Source.
Support for TypeScript is currently limited to Visual Studio 2012, via a plugin, or the TypeScript Playground web-based editor.