Photo from http://www.katrina.noaa.gov/helicopter/helicopter-2.html.

Reportedly, more than 1.1 million visitors to New Orleans have volunteered their time and labor towards the effort to help New Orleans residents cope with the Katrina disaster.  Workers of every skill level have contributed what they can, from painting playground equipment to providing medical assistance.  Three long years after the hurricane, there is still an incredible amount of work to be done.  For more info, see this article by Kristin Butler in The News & Observer of Raleigh, NC.