IBM has filed a patent for "Bionic body armor" that would protect a wearer from long-range gunfire by detecting the incoming bullets and administering small shocks to the appropriate muscles required for moving out of the way. Quoting the patent: "When a marksman (such as a sniper) is attempting to fire a projectile from a firearm, the marksman typically prefers to be as far away from the target as possible, thus giving him or her a head start for the escape after the firing. As an example, the longest reported sniper hit was from a distance of about 2500 meters, resulting in a time of flight of about 4 seconds for the projectile/bullet. Had the target been aware of the inbound projectile, avoiding it by simply walking away would have been possible." After detecting the projectile, the armor would calculate the trajectory and "stimulate the target to move in a predefined manner ... sufficient to avoid any contact with the approaching projectile."
I think that's pretty cool. Wouldn't want to do the implementation, though.