16x60 Grid is a simple CSS framework that we use internally (e.g. Aylis.com is built on it) and is now available as a free download.

The grid consists of sixty, sixteen pixel columns, making a total width of 960.  It has the same founding principles as 960.gs but unlike that system, the gutter space isn't fixed and you can design layouts with 1, 2, 3, 4, 5 and 6 columns of equal width.