The most innovative environmental organization I know of is Seacology, based in Berkeley, CA. It was started by my father in order to provide a way for indigenous people to build things like schools, hospitals and water supplies without resorting to destroying their environment to raise the money. Seacology has won all kinds of awards for the creative way in which it respects the ability of indigenous cultures to take care of the environment, while at the same time improving their opportunities for and access to health care and education. The business model for Seacology is also unique in that every cent of every dollar you donate will to a project-- not to any kind of administrative overhead.
If you're looking into a way to celebrate Earth Day, take a look at Seacology's projects. Maybe even donate a little money-- it's one way in which even the smallest donation make a big difference.