Too many responsive websites fall into the "move the sidebars around" trap and end up looking the same as any other responsive site. By combining the CSS of Zen Grids and the smart markup of the Zen 5 theme, you can create a stellar, unique responsive design for your website with ease.
Zen has always been a popular starting point for building Drupal themes, but the new Zen 5 has been re-written from the ground-up with updated best practices including HTML5, Modernizr integration, Normalize, IE conditional classes, responsive layouts, and, best of all, Sass and Compass integration.
Zen Grids is an all new project, independent from the Zen theme. The Zen Grids system reinvents the flexible, but complicated CSS layout method in old versions of the Zen theme, transforming it into a radically simplified process using the power of Sass. Where traditional grid systems (like 960.gs) often don't scale to match a responsive design's requirements, Zen Grids makes it incredibly easy to create amazing responsive layouts in just a couple lines of code.