Normally this cute IKEA nightlight simply displays some LED-powered colors. With hacked guts, however, it becomes a remote controlled indicator.
The initial hack simply adds in a Bluetooth-based serial controller, allowing you to change the light from an Android phone (or any Bluetooth enabled device capable of communicating with the module, really). It’s a short step from there to toggling the color based on specific input (as oppose to user desire) such as changing color based on the weather or to indicate new messages in an inbox.
Hit up the link below for more information.