The U.S. Department of Defense spends some four billion dollars a year on military simulations and wargames. This area has become much more active in the last decade, as computer hardware has gotten cheaper, and more powerful. You can see this in the photo-realistic games available for PCs and game consoles (X-Box, Playstation). Moreover, simulation is a lot cheaper than actually doing it. Fuel, ammunition and spare parts make training with real ships, vehicles and aircraft very expensive. But for less than a tenth of the cost, troops can practice, with nearly the same effectiveness,  using hundreds of different simulations. 

Perhaps more importantly, simulations are now being created for combat support troops (who make up over 90 percent of the people in uniform). There are now simulations for medical personnel, supply and maintenance troops and intelligence, communications specialists and many other non-combat situations. 

The military has also plugged into the civilian computer game industry, which is turning out a growing supply of tools (3-D modeling kits, terrain creation tools, and editors for creating scenarios and controlling the action.) This makes it much easier, quicker and cheaper to develop military wargames. 

Its easy to overlook how important all these simulation tools are, but they make a difference. Troops who use the simulators a lot are better trained, and prepared, for combat, or combat support tasks. Thats what the troops themselves say, as the simulations maintain their realism and usefulness by getting constant feedback from the users.