I hate the word Drone, UAV is also not used often - quads could mean the wheeled variety and they often have more then 4 motors but most often 4. Toys like the parrot AR Drone are simply very impressive with what they bring to your smart phone or tablet. Aerial photograpy is another avenue of interest but by far and away the most interesting fature of these toys is the fact that you can FPV.
FPV - First Person View. This is where you pilot the model as if you were in it via a camera feed. This allows you to fly it far away and if it goes out of range features like RTH or Return to Home brings the thing right back to where you took off from. There is an amazing video of one that flies out to sea and comes back.