Attach this to a spinning bicycle wheel,
and you get this:
A blue version:
the thing can even connect to a palm pilot to display custom text:
Hokey Spokes are unique bicycle safety lights that allow riders to display computer generated images while riding at night.
I wouldn't want to be seen riding with these lights, but they are pretty remarkable.
I found this while browsing Cool Neon's store.
Speaking of which, Cool Neon sells plastic wires that glow when connected to a power source. You can make some pretty funky stuff using this wire; for instance, check this "modded case" out:
Some of my friends created interesting halloween costumes using Cool Wire. Speaking of which I'm trying to find an excuse to use some too -- it's only $1.00 per foot on sale and it lasts 800 to 3000 hours.