I've been playing eRepublik for over 6 months now, and I can swear that it's the most addictive browser based game ever. You can become a president, a congressman, a soldier, a general manager or a media mogul. The economic system is really simple and complex at the same time. There are 12 items that you can buy, and the production system is as simple as pie. You get food from grain, weapons from metal etc. The political system is a bit simpler than in real life, every country has democratic elections, so no tyrants :) Sure, some group organize Take Overs of countries, but that's not illegal. You have 8 medals that you can win as many times as you can, and every time you do, you get 5 gold. Gold is a international monetary asset, much like gold IRL.

And so much more. Give it a try, it's free and you won't be disappointed.