I live in the Great Lakes region and for the millions of us who do, water is abundant, rain is regular and plentiful, so why would a non-profit organization in Madison, Wisconsin be advocating the use of rain barrels?
A rain barrel acts as cistern that captures rain water from your downspout and and makes it available for use in your garden or perhaps in an emergency situation, even a supply of water that you could purify and use for drinking.
I was greatly inspired when I interviewed Jessie Lerner of Sustain Dane at the Midwest Renewable Energy Fair about the difference that having a rain barrel can make.
[youtube]http://www.youtube.com/watch?v=8O8yTD9DDTQ[/youtube]
Sustain Dane is a not-for-profit organization based in Dane County Wisconsin, which is dedicated to creating communities that deeply enjoy, care for and are sustained by their unique environment. 
For less than $90 you can equip your house with one of these unique rain barrels. Sustain Dane also offers discussion courses that allow you to educate yourself in creating a more sustainable lifestyle and local community along with fellow global citizens.
Learn more at www.sustaindane.org. RainReserve™ focuses on raising community awareness of water related issues. For additional information rain barrels and indoor water conservation kites for kitchen and bath, visit www.rainfordane.org.