The Chaos Computer Club (the hosts of the Chaos Communication Congress) is not just about hacking, but also about the relationship of society with technology. For example, when German Home Secretary Wolfgang Schäuble pushed for increased use of biometric identification (especially in law enforcement), they published a silicone mold of his fingerprint. http://www.h-online.com/newsticker/news/item/CCC-publishes-f... They also recently expelled Daniel Domscheit-Berg (the OpenLeaks guy) from the club. http://www.spiegel.de/international/germany/0,1518,780289,00...
Yeah, there isn't any bigger place in Berlin. Last year I think they were at 120% capacity, because they have such a good relationship with the management of the place that they get access to all the "secret" places. They run their own Phone & Network operation centers etc. There is a server room that attendees can plug their servers into, and CCC made a 10Gbit fiber connection across the city!
The talks at the conference are extremely varied, from crazy-technical to historical to just-for-fun. Here's a list of last year's presentations: https://events.ccc.de/congress/2010/Fahrplan/events.en.html