Twitter has just released a toolkit called Bootstrap. Bootstrap includes CSS for Grids, Layouts, Typography, Tables, Forms, Navigation, Alerts and Popovers.
Use the following snippet to include Bootstrap in your project.
<link type="text/css" rel="stylesheet" href="http://twitter.github.com/bootstrap/assets/css/bootstrap-1.0.0.min.css">

One Comment
Bootstrap is awesome, thanks for the post!