List of shortcut keys for working with the user interface in Windows 8:
Windows key + L: Locks the computer
Windows key + E: Launches Windows Explorer with Computer view displayed
Windows key + C: Brings up Charms
Windows key + I: Launches the Settings charm
Windows key + W: Opens the Search charm
Windows key + K: Opens the Devices charm
Windows key + H: Opens the Share charm
Windows key + Q: Displays the Apps menu
Windows key + B: Switches to the classic Windows desktop
Windows key + M: Minimize all Windows on the desktop
Windows key + Z: Opens the App Bar for the current Metro application
Windows key + Tab: Opens the Metro application switcher menu, switches between applications