HTML /Erb / Haml

• http://html2haml.heroku.com/

Javascript / Coffeescript

• http://js2coffee.org/
• http://js2cs.nodejitsu.com/
• http://cs2js.nodejitsu.com/

CSS / SASS

• http://css2sass.heroku.com/

PHP / C++ :)

• https://github.com/facebook/hiphop-php/wiki/