A friend recently asked me: how to start a Verein in Germany?

What is the difference between a Club and Association?

Both are called "Verein" in legal German.
A Verein does not need to be registered with the authorities, but being so gives certain advantages.
You register (after founding the Verein, electing the necessary officers and authoring the statutes) at the local court (Amtsgericht).
More info (in German): http://www.vereinsknowhow.de/kurzinfos/leitfaden.htm