CoffeeScript is a little language that compiles into JavaScript.
#compiler
Closure Compiler Service
JS minifier from Google. Nice UI for doing it, also has an API for doing it programmatically.
Closure Compiler/Library
“Closure Compiler is a JavaScript optimizer that compiles web apps down into compact, high-performance JavaScript code. The compiler removes dead code, then rewrites and minimizes what’s left so that it will run fast on browsers’ JavaScript engines.”