I noticed that there was a Habitat for Humanity
collection over a the DiscoveryOwners
website. Although it might not be a good fit the POI Megafile it is certainly worth sharing.
The collection features 59 locations around the US (and one in Canada) where they are actively building homes. Email and Phone contact information is given for each location.
If you would like to volunteer this map file will make it easier to find a convenient location. Apparently the pushpins are in the correct post code but not geocoded to the actual lat/long coordinates. You'd need to call for specific location directions.
Thanks to firstname.lastname@example.org
for putting this collection together.