Twitter Bootstrap is awesome, based on less.js, ust add this line in your html code:
<link rel="stylesheet" href="http://twitter.github.com/bootstrap/1.3.0/bootstrap.min.css"> And your page looks already good. If you use css classes like btn label warning danger and much more, you get a right design directly out of the box. Now I want to test it in Sharepoint. Will it work? What do you think? jQuery Theme Roller. Another interesting resources are jQuery ThemeRoller.