I am really interested in developing devices which include a mechanism for supplying their own power. It is likely that we have all seen these in the form of a flashlight that includes a hand crank. I am hoping that we can find ways to expand this technology in a logical direction.
I have heard of gyms which wire up their treadmills to store the energy produced by the constant motion and use this to power the run the lights or the machine itself. I have also heard of specialized clothing which will store the energy that you produce walking around and use this to power handheld devices like cell phone and MP3 players.
If we are going to have a sustainable energy future, we need to begin looking at ways to move away from massive and dirty sources of power to more sustainable and resourceful energy supplies.