A personal interest of mine that I want to explore a bit more in the future. I just bought a ZigBee electricity monitor and I am wondering whether from the signal of the mains one could detect (reliably) the oven turning on, lights, etc. Probably requires Neural Network training. The idea would be to make a simple device which basically saves you money by telling you how much electricity you are wasting.
Then again, its probably already done by Google...
I have never understood the flying part of these things. Isn't it really impracticle to have all those tiny quadrocopters zooming around. My money is on holography or still a google glass type of device, if only considering the energy requirements for doing anything kinetically.