My Open Brewpub Map is another example of what can be done with free geodata from OpenStreetMap.
Basically a combination of two of my hobbies (brewing and mapping) in some way :)
I want to motivate mappers to tag Brewpubs with the appropriate tag (microbrewery=yes). All pubs and restaurants (or even more exotic stuff like monasteries) featuring this tag will get automatically displayed on this webpage.
Recently I get emails asking me about adding missing brewpubs or hints about wrong entries. Well, this project is not about me doing a worldwide database of brewpubs, but like Wikipedia everybody is invited to help. If you don't like to do this yourself (which I would regret) just submit a bug report using the notes feature thus some mapper living near this place can do it for you.
The map is using a permanently updated PostGIS Database with hstore extension.
The kml-file and detailed POI information for the Openlayers map is generated from PostGIS by means of two python-wsgi-scripts.
Of course they are available as free Software:
git clone git://git.geggus.net/brewmap.git
Alle this stuff is running on the FOSSGIS devserver.