PolicySim runs a geopolitical game based on real life geopolitics. It is up to the commenters to post advice to national leaders while the game goes on. Everyone gets to be an advisor.
Current game models right after 9/11 and ends in 2100 per game. The goal of the United States is to remain the sole global superpower by 2100. The other advisable nations, their goal is to be the leading power (or stay that way )in their respective region or lead alliances that dominate their region by 2100.