This is CoffeeScript
I don't subscribe to the notion that you can write code faster with less keystrokes (vi/emacs, anyone?). I do however, understand that a cleaner syntax would lend some readability and simplicity to your code once you learn said syntax. 
Ultimately, I find that the problems that CoffeeScript solves, and solves quite well, are not really that big of a deal for me given that I've been working with Javascript enough to get used to the quirks. 
I'm not sure if I'll ever use it myself, but I can't blame anyone who would; this article does a good job explaining some of the benefits.