Hackers over at MyDigitalLife have enabled the following features using registry keys:

Windows 8 Ribbon UI
Create the following key in registry: HKEY_CLASS_ROOT\CLSID\{4F12FF5D-D319-4A79-8380-9CC80384DC08}
Create a string value under the key called “AppID”, set its value to “{9198DA45-C7D5-4EFF-A726-78FC547DFF53}”
Kill explorer.exe and restart and the Ribbon UI will be enabled.