Sports arenas are not the first thing that comes to mind when you think of green buildings. With their flashing light displays, tons of waste from vendors and food services, and the occasional case of Astroturf, stadiums have a lot to overcome when it comes to going green. Even so, there are a number of big sports complexes making a real effort to help the environment rather than hurt it. Here's our list of seven of the greenest sports complexes in the world. (Text: Bryan Nelson)