Over the past year or so, I've looked into a variety of options for reflective materials and lighting that can easily be worn for cycling and running in the dark. To be useful for a variety of sports, a light would have to catch attention from a good distance, be light-weight and comfortable, and be easy to attach to different clothes, backpacks, bike luggage, etc.
One of the products that I have been impressed with (at least from reading about it) is the Flashbak. The Flashbak is a set of strips containing ten bright, flashing LED's that can be seen up to a mile away. It can be attached to almost anything and runs on 3 AA batteries, which I think would give it great flexibility and potential longevity.
Here are some pictures from the Flashbak website:
A few months ago, I left a comment on the Flashbak website asking a question about the product, and the awesome Brad contacted me about trying one out.
He's going to send me one to put through the ringer and report to all of you how it goes. I'm eager to try it out for commuting by bike in the mornings and for running in the late evenings. In addition to attaching it to my back or a backpack, I hope to try wrapping it around my traffic-side arm, as well.
Check out the website at http://www.flashbakonline.com/ for more information about the Flashbak and watch for a post in the future detailing my experience with this visiblity option.