The organization of events happens on the QGIS wiki.
Pre-2013 events are listed below:
On 20th September 2013 the 7th german-speaking QGIS user meeting took place in Kassel. The event was organized by Otto Dassau (QGIS project) and Dr. Claas Leiner (Serviceportal GIS und Geodaten am FB 06 der Uni Kassel) and supported by the german FOSSGIS Association. This time, 80 users, developers and other interested participants joint the meeting to discuss about QGIS. Besides practical reports and individual experiences, workshops were at the center of the event.