1) The Sahara Forest Project: It may sound crazy, but an organisation aims at making available a new source of fresh water, food and energy in hot, arid regions - the Sahara. That would solve many problems in the region if it is implemented. The great thing is that they will use only eco-friendly technology to do it: solar power, seawater greenhouses and nutrients. Check it out.
2) A solar powered blanket for African countries. This way, they can recharge their cellphones (mobile technology in Africa was found to be extremely useful for health information for people with HIV and Tuberculosis, for example), and use the blanket to light a bulb in their homes at night or use it to heat some food - it provides up to 10 hours of energy once the battery is charged.