Blog Action Day is October 15. This year the topic is water.
I don't know if a bunch of people blogging about global water issues really makes any difference, but perhaps it will educate some who will make a difference. This year more and more blogs of note are getting involved (including the White House, apparently).
I read somewhere that more people have cell phones than access to clean water. Who decides that kind of thing? I don't know what kind of severe estimation goes into that analysis, but nevertheless, I believe it's probably true.
When I was in Mokattam, a slum of Cairo, Egypt, it seemed like more families had satellite dishes for their TVs than they had food to fill their dishes.