Go solar! Ok, I bet you're looking for things that can be accomplished on a smaller budget.
We built a wind turbine in our yard using scrap parts from our local Habitat for Humanity ReStore. It was awesome. Then the homeowners' association told us to take it down. That was considerably less than awesome.
And... here's a picture of the wind turbine:
http://members.cox.net/robertfirth/kc_star_wind_turbine.jpg
So, that's my suggestion. If you have a project that requires wood or any other building materials, check out your local Habitat for Humanity ReStore before buying it new at a Home Depot or Lowes.
http://www.habitat.org/env/restores.aspx