Less
Less is more in so many ways.
Paging Mark Nudelman
There is of course the pager for Linux and other operating systems called less http://www.greenwoodsoftware.com/less/
Le CSS preprocessor
Less is a CSS pre-processor, meaning that it extends the <abbrev title="Cascading Style Sheets">CSS</abbrev> language, adding features that allow variables, mixins, functions and many other techniques that allow you to make CSS that is more maintainable, themable and extendable.
Less runs inside Node.js, in the browser and inside Rhino. There are also many 3rd party tools that allow you to compile your files and watch for changes.