The (Rise and) Fall of Nations (link whore)

MaskedMuppet writes "A coworker of mine stumbled across this online nation simulator, that's free, rather addictive and has a prize every round. It's a numbers puzzle war game where the pieces are the other players. We're in round one now, and it lasts til the end of November. The prize is a GameBoy Advance SP. Manage armies and resources, and pick on your neighbors..."