c47439d4_of_Windows_8_Keyboard_Shortcut__Description
[Keyboard Shortcut] Win+M / Win+Shift+M [Description] 
Minimizes every window. It works like Win+D, but it isn't reversible when you press the combination again. You must press "Shift" along with it in order to restore the windows.
Useful List of Windows 8 Keyboard Shortcut
Description