Small amounts of money can go a long way in the developing world. This is such a neat idea connecting it so small debts we owe our friends. I hope this app really takes off. 
springwise:

Small debts among friends turned into charitable donations
It only stands to reason that the easier it is to give to charity, the more donations will be made. We’ve already seen a few different efforts to elicit donations via rounded-up credit card purchases or even unused subway fares, but recently UNICEF Germany came up with another tactic: an iPhone app that enables friends who owe each other small sums of money to pay off their debt through a charitable donation instead. READ MORE…