previous post, I was thinking about how to connect the game world to the real world so that the game was not ABOUT sustainability, but actually required sustainable behaviors in order to play. In that post, I mentioned using smart meters as "input devices" and augmented reality as two possible approaches.
Here are a couple more thoughts:
Use the Kill-a-Watt product, modified to tweet your electricity usage, in order to easily report energy usage over time. By tracking usage changes, giving points for number of connected electricity monitors, creating special achievements that require certain energy usage behaviors and teaming up with others to pool points to perform in-game actions, you can link real energy usage to the game's outcome. By making the interface a tweet instead of a manual entry the game can focus on action rather than data entry.
Reverse my thought - pay for sustainability through proceeds of the game's sales or in-game economy
Maybe my thinking about requiring sustainable behaviors to play isn't the right way. Maybe a good alternative is to fund other peoples' sustainability activities by playing games. Puff Puff : Gulf Spill is an iPhone game that donates 10% (or 30% depending on whether the article or the video is correct) to habitat restoration. Donating proceeds from sales to a charitable cause is not a new thing, but attaching it to a game is new.
Attach it to a game with an in-game economy (e.g. World of Warcraft, Second Life, EvE Online, etc.) and give the option to the player to donate some of their in-game money to real world causes (instead of cashing it out as real-world money or selling it to someone else for real world money as is done on eBay) and it might be useful.