http://www.navyfield.com/
It's a MMO "tactical simulation." Basicly, you have money, buy a WWII era ship (you start with a frigate) and work your way up to a battleship or carrier. You've got to hire a crew, buy guns, fire control systems, engines and ammo. Your crew levels up with XP that is used to gain access to bigger ships and guns. It's pretty addicting. It's a free beta at the moment, so check it out.
