Coffee Script

An emerging contender in the SmallestFederatedWiki. Or so it seems.

is a little language that compiles to JavaScript.
It adds useful features and smoother syntax while compiling to clean, readable JavaScript.
You can use it anywhere you use JavaScript: in the browser, or on the server.
has exploded in popularity since April 2011.
It was talked about in every other presentation at JSConf.
It’s made enough waves that some language features popularized by CoffeeScript are planned for inclusion in future versions of JavaScript itself

Proprietary and fee-based?

Looks free to me. Do you see otherwise?

I could have sworn I saw a "Purchase" button. It's gone now. Scratching head. Maybe my PC is infected with spamware :-)