Many people have been asking how you turn your nook on or off, it is not the N button below the touch screen, on the side of the unit, on the top left hand corner is a button that looks sunken into your nook color. Press and Hold the button until the screen loads.

If you want to shut your nook off, you can again hold and press that button, you may see an android prompt if you want to put your device into standby or power it off, do as you will.

Its best turn the device off if you are not using it, as it still eats a fair ton of battery even when in standby mode.