From Gizmodo.com:

"According to Merriam Webster fulguration means "the act or process of flashing like lightning" and that's kind of the principle behind artist Julius von Bismarck's device. It's a reactive flash image-projector... or, to put it another way, a real-world hack of other people's photos. Sounds sinister, looks sinister... works great. Adapted from a flash gun and an old SLR, it senses the flash of someone's camera, and then quickly illuminates itself, projecting images or text onto the object that was being snapped. The video of bemused tourists in Berlin, peering in confusion at the screen of their digicams is priceless.

Julius' web page says one of the reasons he built the gizmo (currently being patented) was to challenge the high confidence that people have that their photos are accurate captures of reality. And though, as Ghost in the Shell fans will admit, it's no sophisticated Laughing Man hack, I love it for the fact that it's a physical trick as opposed to a digital one. [Juliusvonbismarck.com via MAKEzine]"