This is a great video that shows how the solar bottle-bulbs are being used in the Philippines. Although not graphic design - this shows how lateral thinking and the use of available resources can be used to create something that is cost efficient, sustainable and improves peoples lives.
It's a simple solution that uses recycled materials and the refractive properties of water. Apparently this was designed and developed by students from the Massachusetts Institute of Technology (MIT).
If you're interested, here's a link to a high quality image that shows instructions to make your own!!