Parking Lot Car Finder
My idea is to have a small lens located near your car antenna. When you have forgotten where you've parked, you click a button on your keychain and the small lens shoots either a bright colored light up into the air, or it beams a personalized hologram above the other vehicles, so that you can locate your car quickly and easily.
Reward: For my reward I would like a new Toyota FJ Land Cruiser. I've never owned a new car.