Recently I have been playing around with a dynamic stylesheet language: Less. Less extends CSS with dynamic behavior such as variables, mixins, operations and functions. LESS runs on both the client-side (IE 6+, Webkit, Firefox) and server-side, with Node.js (which can be downloaded here ). I like how you can specific a variable in one place, then call to it anywhere in the stylesheet, this simplifies to search and replace feature when you have to make a global change.
My favorite feautre is that I can set nested rules rather than contruct long selectors names to specify inheritance. Cleans up the stylesheet and makes it shorter.