I met Akvo in the Netherlands - a group that not only is working for water and sanitation, but really gets the importance of doing all this in an "open source" way.

Much could be written... but more than anything I want to share these wonderful posters. (Note, these are under a CC-BY-NC license, i.e. may not be reproduced for commercial purposes):

See Akvo's blog to learn about the man behind those amazing Akvo posters.