SMM: Green Gamer
If everyone on the planet lived like you, how many Earths would we need?
Roughly a quarter of the Earth's surface (land and water) is biologically productive, and a global acre represents the average productivity of that part of the Earth's surface. Global acres account for the fact that the Earth can only regenerate itself at a set rate.
If you divide the number of global acres by the number of people on the planet (6.6 billion), then each human's fair share is 4.5 global acres. So, if your lifestyle requires more than 4.5 global acres, you're using more than our planet can sustain.
You create a character (cute cowboy hat, huh?) and answer questions based on your lifestyle, and the game computes how many earths we'd need to support our population if everyone lived the same way. Like a carbon footprint score, but different.
The game is not without its flaws. For example, my utilities are included in my rent, so although I try to conserve whenever possible I can't say how much they cost each month. There's no way to say you don't have a car. Also, there's something fishy going on with the transportation scores: I walk almost everywhere, take the metro maybe once a week and a cab once a month or less, but somehow I still scored a full "global acre" for transportation. Food was the biggest eye opener, with three global acres. Must be all the coffee.
Siel at Green LA Girl has a great roundup of eco-edutainment games if you're looking for more Saturday time wasters. Happy weekend!