Great designs often leverage two or more environments, and that is precisely what the Lightclip by Cyprus-based Lab02 does. It's a 3D printed attachment for your iPhone that makes use of the rather bright light on the iPhones to produce a variety of lighting effects.
At this time four different Lightclips are available. The "Ghost" version is a white "ghost" that glows softly with brilliant eyes. Just attach and light it up with any common LED flashlight app.
Our favorite Lightclip is "Batman". When lit, a classic Batman logo appears on your ceiling.
If you'd like to have your own Ghost, Batman, Ninja Ghost or Swan, you can purchase them from Lab02's Shapeways store at a price of between USD$16-17, depending on color.