Backbone

Backbone

 * http://backbonejs.org/

Ember

 * http://emberjs.com/

React

 * http://facebook.github.io/react/

Bootstrap

 * http://getbootstrap.com/

Foundation

 * http://foundation.zurb.com/

Sass
css with power
 * http://sass-lang.com/

Less

 * http://lesscss.org/
 * http://lesscss.net/

stylus

 * http://learnboost.github.io/stylus/