Another amusing and absurd fact from the German unemployment bureaucracy is that you are not allowed to work on open-source projects while unemployed, because it's "work", and people that work don't receive unemployment benefits.
Getting a bit defensive, I argued it's less like work and more like training for getting a job, and I've been told that it's the same, if I'm taking part in training that *they* haven't provided for me, then that's also considered as reason to not being "unemployed".