I remember having a lot of fun with eRepublik. It was similar to BM, but in a more contemporary setting.
It's too bad they massively updated it. At first I thought the update was great, but then I realized how much all the new complexity made the game take even longer to play daily and the new war system was way too time intensive of 1-2 hours a day. Whereas before I could run a company, be a congressman, and fight in a war every day within 5 minutes. Haven't touched the game since.
Another game I recall playing a long time ago is Renaissance Kingdoms. Very similar to BM, but more on a personal scale rather than macro. Thousands of players take the roles of peasants and craftspeople in individual kingdoms. Think I might try it out again sometime.
http://www.renaissancekingdoms.com/
