Photo: xdamman on flickr
We don't collect enough weather data from the atmosphere (or ocean). We also would like internet service everywhere on the planet. Let's solve both problems at once:
A 3D grid of tiny flying drones that collect temperature, humidity, wind from every location and elevation, and also serve as a mesh network ISP that provide internet access to everywhere on the planet.
Ok, maybe it wouldn't really work. Oh well.