Deway is organizing a full weekend Mapping Party + Hackaton around its "map of the commons". Join to share your local knowledge or your technical knowledge to work on integration in the OSM data.
More info and obligatory registration: http://dewey.be/cartopartie/cartopartie-bruxelloise-au-pianofabriek/
Most of the OSM community will not be present on Saturday, as we have the National Mapathon (nationalmapathon.eventbrite.com).
However, we will be present on Sunday to work on OSM.be projects for our second OSM Belgium Hackaton.