Modification of the board game CO2. The original is a nice game but not very realistic in terms of the economics and policy mechanisms of climate control. The mod allows accurate simulations of global climate policy options such as emissions permits, carbon taxes, clean energy grants, and need-based exemptions. The mod is under development and a paper concerning it is under review at the International Journal of Serious Games.
Update December 8 2015: Isaac Knowles helped me on the paper and it was accepted. Yay! You can get it here:
If you download the paper and go to the appendix, the full rules for the mod are included there. You would need to buy the original board game CO2 in order to play the mod.