GPS Shirts & License Plates
I'm sure this has happened to others as well: You're in an unknown neighborhood, basically lost, but there are a few cars, bikes or even pedestrians around who seem to know where THEY are going. If one of them had the same goal as you, you could simply follow them. But then, how would you know...?
Here's where GPS shirts and license plates come to play. The license plate idea is kind of easier to implement: This would be a display beside your actual license plate which is attached to your real GPS in the car, and so the folks behind you can see where you're going.
The shirt would work similarly, with the place you're heading to displayed on the back of the shirt (either automatically via GPS, or to be inserted manually). Of course, it is nice to imagine this idea in an analogous and visual way - nowadays, however, you'd be more likely to implement it virtually: Create an app, have people enter their routes, and off you go.
Reward: One of those.