Industrial Progress is a very important and practical cause, and this group has a very effective leader who is actually having some effect at persuading people (particularly people in industry) and providing them with better ideas. And it's cheap. SENS needs a billion. A few hundred thousand would be huge here.
I second this recommendation, CIP has been doing an amazing job at showing how and why industrial progress is amazingly beneficial to human prosperity, while dispelling the common critiques the "green" movement uses to dispel this idea.
Both SENS and CIP are hugely important ventures that people should look into in my book.
Here is another place with high value per dollar:
http://industrialprogress.net
Industrial Progress is a very important and practical cause, and this group has a very effective leader who is actually having some effect at persuading people (particularly people in industry) and providing them with better ideas. And it's cheap. SENS needs a billion. A few hundred thousand would be huge here.