Hello,
OpenStreetMap has an assembly on the Chaos Communication Congress 32C3, December 27th to 30th, 2015, CCH Congress Center Hamburg, Germany.
Last year over 12,000 hackers from all over the world visited the event.
If you want to join us you may sign on the OSM Wiki:
https://wiki.openstreetmap.org/wiki/Chaos_Communication_Congress/32C3
Regards
Tirkon