Adaptosarus is a fine blend of media query tricks, I am continually using in my responsive projects. I enjoyed using Skeleton, but I found that a max 960px grid made my designs feel outdated on modern displays.
I took what Skeleton was and reworked it to suit my needs. Chopped the 16 columns to 12 and opened up the margins. Responsive break points for modern displays, tablets and mobiles. Old browsers most likely mean old devices. Those folks will be served up the 960px version which will look great. Now that tablets are sporting high resolution displays; you can find Adaptosaurus packed full of media queries to handle that.
Respect/thanks to Dave Gamache, Paul Irish, Ethan Marcotte and anyone else doing their thing in the responsive world.