As a follow-up to what Dan wrote about military simulations, they've been a staple in the flight training community for years, but are now being used for new applications. In fact, I'd bet that a lot of today's cheap, powerful graphics cards for home computers are due in large part from the R&D investments made by the military a long time ago. A major player is Evans & Sutherland, who created the graphics system for the simulators I used while learning to fly helos in the Navy. BTW, the instructors that had been around a while said that the students coming through the training pipeline at that time performed better than in years past. Their theory was that pilots who were then getting into the cockpit (late '80s) were the first to have been raised on video games, and thus had improved hand/eye coordination as well as better multi-tasking capabilities.