http://www.youtube.com/watch?v=PqMS_xEsUIw&feature=player_embedded
The Longreach Buoy fires a bullet-like projectile which expands into a foam buoy in fifteen seconds upon contact with water. It can be shot up to 500 feet, allowing rescuers to potentially save more people.
This won the 2010 James Dyson Award for design. Fast Company features it and two runners-up; an inflatable raft that turns sea water into drinkable water and an automated CPR device.