http://cisr.nps.navy.mil/cyberciege/index.htm

CyberCIEGE enhances information assurance education and training through the use of computer gaming techniques such as those employed in SimCity™ and RollerCoaster Tycoon®. In the CyberCIEGE virtual world, users spend virtual money to operate and defend their networks, and can watch the consequences of their choices, while under attack.
A limited distribution version of CyberCIEGE is now available at no cost to agencies of the US Government.