About six years ago I did some brief experiments with ‘light painting’: photography using long exposures where you move the light sources around while the shutter’s open:
Click the image for a couple more…
My friend Karen has done this on a rather larger scale, for example by running around bits of Thetford Forest in the middle of the night carrying big lights:
But she’s also just pointed me at a lovely example of what you can do by bringing this up to date and using iPads as the light source. Making Future Magic is a creation of the Dentsu London agency, and is beautifully done. Worth clicking the full-screen button.