Lights

Good idea. That scotchbrite (?) stuff lights up like a flare when hit with light - shame it's so expensive. My cheap commuter spd shoes have a couple of strips on the back edge anyway.

It's quite cheap if you don't buy it in a cycling context
http://www.fabricuk.com/showspecial.php?id=51

£1.49 for 1m of 25mm wide tape.