A new tool from Stardock allows you to run Metro applications directly from your desktop. Metro apps, or Modern apps as Microsoft likes to call them, run full screen by default and can only be started from Metro start screen. With ModernMix it's possible to run Metro apps in separate windows that allow you to minimize, maximize or close them as you're used to from normal Windows applications.
The ModernMix Beta is available as a 30 day trial but can also be bought for $4.99 for which you will also get access to the full version once it's released. The software is also part of Stardock Object Desktop that includes MetroMix, all mentioned products and more and costs $49.99