For those who need just the Twitter Bootstrap CSS grid, here is it!
Bootstrap’s responsive grid and responsive utility classes only, without any extras. Lightweight yet still powerful. Style to taste.
Include one of the precompiled grids (grid12.css, grid24.css, grid30.css, grid100.css) in your site, or customize and compile grid.css.less with command line lessc or LessPHP (no extends are used).