Light pipe is very cool stuff. It transmits light along its length, like fiber optic cable, but it also "leaks" light along the way, causing the entire length of tubing to light up when a bright light is shined into one end. It can be easily cut to length with a pair of scissors or a knife and by using a piece of shrink-tube to attach a super bright LED to one end, you can produce an EL-like effect. Light pipe is great for decorative applications, you could even sew it into an e-textile project. It's also a good way to 're-route' an indicator light that's buried inside an enclosure, so that it's visible on the surface. Putting different colored LEDs at either end produces some very cool effects as well!

This is a 1 foot length of 3mm diameter light pipe. This light pipe is clear and can be easily connected to a basic 3mm LED with a length of shrink tubing or some tape.