Video by Paul Fraser.
Totally amazing find from SIGGRAPH 2010: a modular LED display that can be written on using a light source, like a laser pointer. Now, instead of programming scrolling LED displays, just write on them and be done with it. The piece is by Junichi Akita, an assistant professor at Kanazawa University in Japan.
The tiles are pretty small, and can be joined together along any edge to create an infinite variety of shapes. Once connected, the tiles act as one, seamless unit. Like any LED display, modes are incorporated, from the traditional side to side scroll to the more unconventional tilt. Watch Core77 correspondent Paul Fraser's video from Siggraph above for a real time demonstration or Akita's video below.
There isn't much information on this out there on the web, but you can read Akita's technical paper here.
Video by Junichi Akita.