P2P cell network
Create a cell network whereby each cell phone "forwards" the call to the recipient. Example: I am location A and want to speak to my friend in location B, X miles away, let's say 10 miles. I call him/her and the cell phone transmission hops and skips through other users' idle phones until it finds my friend.
Network would take advantage of users whose phones are idle - on, but not in use - to transmit and amplify the calls. Each cell phone is connected to the network and is standing by to assist in passing voice/data to/from the two parties.
This could be very useful in developing countries and/or rural areas where range is necessarily limited and no cell phone provider is willing to provide service.
Reward: A piece of chocolate cake with ice cream and a candle.