To shut down an app in Windows 8 / RT: Left swipe in / out to get the task list; Select any other app, I use "Desktop" for instance; Left swipe in / out again - this will display the app you "were" in (that you are trying to close) in the left-side task list; Select-hold, drag right and down down to the bottom. The interface will either.. refocus to the app you are trying to close, or will actually close. In practice: Toggling first to desktop helps, and normally allows the app to close; Toggling to the Metro home screen pretty much always does not work, the app ends up not closing and taking focus. And more odd: The active-app you are in is never displayed on the left. My Microsoft friend says you don't need to close apps; that the memory management on the device / OS will "take care of itself". I find that not be the case in that closing helps free up resources, and is the only way to restart tanked apps. Lastly: When you are down to only one running app + the home screen (always running?), you cannot close any apps, you can only toggle between them.