Selectivizr : CSS3 pseudo-class and attribute selectors for IE 6-8
lit : a ridiculously small responsive css framework
Galen Framework : Automated testing of look and feel for your responsive websites.
Layout testing seemed always a complex task. Galen Framework offers a simple solution...
YAML Builder : A tool for visual layout development of YAML based CSS layouts
Skeleton : Skeleton: A Dead Simple, Responsive CSS Boilerplate for Mobile-Friendly Development
