Significant whitespace is used instead of braces to delimit blocks - a fact that will keep discussion forums buzzing, although it is in line with other recent languages like CSS3 extension Sass, Haml, etc.
Coffeescript has been around for about a year, and has recently gained exposure through a few public projects that used it. ArsTechnica's iPad application is written using HTML and Coffeescript and runs as native application using PhoneGap. 37Signal has published Chalk, a whiteboard app that runs on the iPad and uses HTML5 features, such as the Cache Manifest, to run offline. It also uses Coffeescript.
C and C++ code can be translated using Emscripten and the project's site has a few demos of translated C and C++ libraries. However, it also has demos of translated versions of Python and Lua runtimes.