Check out http://www.givewell.org/charities/top-charities http://www.givewell.org/charities/top-charities if you want to maximize the impact of your donations r

Check out http://www.givewell.org/charities/top-charities http://www.givewell.org/charities/top-charities if you want to maximize the impact of your donations regardless of the target domain. For something specifically of interest to hackers and entrepreneurs take a look at CFAR (http://rationality.org/ http://rationality.org/). They are a non-profit that teaches decision making skills.