Here's a great tutorial by Benjamin Zaitlen on how to make your own Lilypad Persistence of Vision wristband.

As Zaitlen explains:
"Persistence of Vision (POV) is the illusion that an image continues to persist even though the image has changed. In essence, we are taking advantage of the limitations of the brain-eye processing time. With a camera we can tune our eye for a longer exposure. The Lilypad POV (row of LEDs) is a fun toy to build with minimal programming and electronic needs."

What a fun project! Can't wait to try it out sometime.