Chaos Computer Club (CCC) e.V.
The Chaos Computer Club is Germanys oldest established Hacker organization. I've been a member since 1998, the year in which I first visited their (15th) annual Chaos Communication Congress.
The CCC is a club of tech-savyy hackers, who like to play (and create) new technology. They are just as much a political club, participating in debates about civil liberties in the digital age, data protection and security in government use of technology, intellectual property legislation, etc.
I've been contribuiting in various ways to the work of the CCC, for example by volunteering (and later running) the video recording team for some years, and by presenting about a variety of technology security related topics at many events.
Chaos Computer Club Berlin (CCCB) e.V.
This is the local subsidiary of the CCC in Berlin, established as a separate legal entity. Berlin is undoubtedyl [one of?] the most active local CCC groups, carrying the burden of organizing the annual congress and the Chaos Communication Cmaps every couple of years, as well as hosting the editors of the Datenschleuder magazine.
There's also a lot of work on various subjects, such as research in RFID security, video surveillance, and to some extent (Berlin is the capital, after all) lobbying.
From 2003 to 2010, I was a member of the Board of CCC Berlin e.V.
Kommunikationsnetz Franken (KNF) e.V.
This non-for-profit Organization had taken up the cause to provide individuals with Usenet and Internet connectivity in 1993. But it's not only about connectivity, but also with access to Internet technology.
KNF enabled me to get TCP/IP connectivity over SLIP (later PPP) and HDLC-over-ISDN in 1994/1995. Starting from 1997, I had an analog leased line with 33.6kbps modems. Given the situation of the Internet in Germany at that time, this was really 'at the bleeding edge'. Individuals outside university research rarely had the opportunity to connect to the net. Commercial Internet Service Providers were only in the process of being created, and targeted only business customers.
Later, in 2000, the analog leased line was equipped with Pairgain DSL Modems, providing 2Mbps symmetric bandwidth.
At KNF, I had the chance of obtaining hands-on experience with the operation of Internet technology, including server and network operations, dialup infrastructure, network security, etc.
Had it not been for KNF or other similar organizations, and/or would I've been born a couple of years later, this chance of "learning the real internet" would not have existed. A time where the term dynamic IP address didn't even exist yet.