Test your site in various devices from an iPhone and iPad, to a Kindle and on Android on the Responsinator. It also shows your site both in portrait and landscape mode. I like this tool much more because of the outlines of the devices displayed on the page, which brings more meaning to the whole process.
20 Responsive & Lightweight CSS Frameworks for a Fast Start
Zurb – ResponsiveTables Have you ever wondered how to deal with the big data tables in responsive design? Zurb, a CSS/JS combo gives you the answer; it takes the data tables and modifies them so that they do not break the responsive layout on smaller screen devices.