Multiple Integrated Laser Engagement System: Laser Tag for grownups.
MILES is a central element in the US Army's training program from the soldier- to brigade-level simulated engagements. Almost every weapon, vehicle, or person can carry a MILES device. The transmitters are attached to weapons, the detectors are attached to vehicles and soldiers. Any time a weapon is "fired" (using a blank cartridge, so as to simulate real-world pyrotechnics, noise, and reloading issues), a laser sends data along a legitimate trajectory and range for that particular weapon. At the receiving end, the data is interpreted and registered as a hit and subsequent action is taken by the MILES detector. For example, an M1A2 Abrams MBT hit by an M16A2 round would indicate that it had been "hit" by a bullet, but the tank would experience no ill effects. On the other hand, if an M1A2 fired it's 120mm canon using a simulated high explosive round, it would transmit a different laser signal to the expected target area. Any infantry in this area would receive the signal on their MILES unit and they would be removed from the engagement simulation (usually by sitting down and removing his or her helmet).
MILES was developed in the 1970's by the Army and is still used for the most part in it's original form. An enhanced version, developed starting in 1993 and dubbed "MILES 2000," includes radio communication in addition to the laser data transmission to allow for more versatile weapons system simulations. MILES 2000 is able to keep track not only of whether someone or something was hit but who was responsible for disabling it.
The original MILES equipment is still used for training at many Army posts and the MILES 2000 is primarily deployed at the National Training Center at Ft. Irwin, California, although it has been deployed at some other bases to a lesser extent. | 
