Whilst trying to increase my screen brightness I accidentally held down the Windows key instead of the Function key on my Dell laptop.  Much to my surprise, the window I had selected Maximized. Pressing the down error made it restore.  

I played around with it more and came up with these sequences:

Windows key + up:  maximizes a restored window
Windows key + down: restores a maximized window, mimizes a restored window
Windows key + left:  left tiles a restored window, restores a right tiled window, right tiles a left tiled window, ad infinitum
Windows key + right:  right tiles a restored window,  restores a left tiled window, left tiles a right tiled window, ad infinitum

The left and right keys basically loop through all of the options except for maximize and minimize. 

Pretty useful I think!