Last December, Greenpeace put out a simple two person game called Deep Sea Desperation that focused on protecting ocean habitat for the Greenpeace player and drilling in more difficult places for the Big Oil player.  Lots rather fun.  The main page is here, while the rules are there.  There is a lively discussion about it at The Miniatures Page.

Apparently someone else came up with a game called Save The Whale! about eco-warriors vs. whalers.

Both games are free and look fun to play and educational as well.