Alex Gibson is a talented web and mobile developer who shares my views on HTML5, mobile web development, and responsive design. In this post on his blog he gives a thorough run through of how he re-designed his web site. He went mobile first, responsive and explains, among other things, how he setup his media queries. Furthermore, he explains how he re-orders content of the page depending on the device, using CSS. The web page is pretty simple, but serves as a nice case study of a mobile first, reponsively web designed, HTML5 site.
Be sure to check out his blog at http://miniapps.co.uk/blog/.