"NationStates is a popular, online nation-building game at http://www.nationstates.net/
A player creates one or more fictional nations. The NS game provides a (possibly amusing) description of each nation, and ranks all nations by 'Civil Rights', 'Economy' and 'Political Freedoms'. The World Census compares all nations. A player can affect its nation by deciding issues, or by participating in the World Assembly.
Players can also roleplay their nations. Roleplay never affects the description or rank in game, but roleplay is the only way to hold national elections, make exports, fight wars, play football, or otherwise explore their NS nations beyond the limits of the game. Players can also create wiki pages about their nations."

It's actually pretty fun, if you can get into a good region.