Did you notice that yesterday was UN World Toilet Day? Lack of sanitation is a big problem in the developing world. According to the Gates Foundation, which has adopted sanitation as one of its key priorities, 40% of the developing world practises open defecation or has poor sanitation - that's 2.5 billion people - a direct cause of 1.5 million child deaths from diarrhea a year.
The Gates Foundation's 2012 Reinvent the Toilet competition awarded prizes to university researchers at California Institute of Technology, Loughborough University and University of Toronto and awarded second round grants to other institutions. A common theme of these toilets is to extract energy and clean water from human waste - win-win for sure. See the Gates Foundation press release here.
For a great introduction to this topic, watch Rose George's witty and informative TED talk entitled Let's Talk Crap.