A good friend of mine is in the process of starting up Green Laces - a program to do exactly what it says - provide green shoe laces.
Their goal is to work with 1000 Olympic athletes from 10+ countries for this summer's games to supply them with green laces (in both color and materials.) Wearing bright green laces, inevitably fans and the media will wonder what's behind it, and these athletes will be have a global forum to voice their personal pledges to lead greener lifestyles and hopefully inspire others to do the same.
Anyway, I can definitely see this getting some attention and traction at this summer's games and I applaud the Green Laces team for their noble efforts. While the site isn't completely up yet, you'll be able to buy your own green laces and support them soon.