I talked to Dr. Micah Altman at Harvard recently and he has a pretty good idea for a project. In short, use Open Source technology, and write some more, to create a web app that will let anyone draw their own maps. From there, build a community process where people share and discuss their maps. Maps would be accompanied by automatic statistical reports.
Current Open Source technology in the form of Geo Server can render map data and display it in a slick tiled, scrollable webapp kinda like Google Maps.
Eventually it needs a social site with map pages posted by some owner and comments off that (possibly a community-blog format, with the posted maps being a user's "diary" entries).
Related technologies: Open Layers maps. PostGIS geo database.