IE 10 Preview, wow, this is a great way to learn more about Modern Design and get into the right mind set for Windows 8 Store Apps.  No kidding.

Let’s say you are using one of the trailing edge operating systems like Mountain Lion, and you want to get into the new way of design software, then take a look at IE 10 Preview.  Light, interesting and easy to design, it’s a new look this modern software design stuff from Microsoft.

http://ie.microsoft.com/testdrive/ 

Fun things that should not be used at work (unless you are a game designer):

The Arcade, an awesome package of fun, fun, fun.  And excellent design example.