It would be easy to collect and provide geographical data such as positions, latitude, longitude and latitude... anyone with a GPS could contribute. Uncharted areas could be covered fairly easy. Big companies in this area charge for their data, an open source initiative could provide pretty much the same or similar data under some licensing and/or take donations. The collected data should be free to the public... as data describing the geographical landscape around us can't really be someones property.
I remember a project that had to close down after some organization put their foot down, lots of people had collected UPC/EAN bar codes from items they had bought. For some reason that data were in some way offensive and the project was abandoned. Bar codes are put on almost everything, so it can't really be illegal to collect and make them searchable. Information about bar codes is also quite hard to come by, but there's plenty of companies that sell ready-to-use packages/components for software development, often with a hefty price tag.
I'd like to have a cellphone with GPS... to pinpoint favorite spots and find my way to new places. There is some but they are expensive... I'd rather have GPS functions than cheap-ish digital camera functions... as I already own 3.3 and 8.0 Megapixel cameras.
I also found an interesting project, geographic positioning of IPs at hostip.info, even contributed with some data.