They are all hobby, on top of my work time. Many of the attendees are there for fun, especially on eurucamp, off their own pocket. Obviously, 3 days of meeting with 300 international people isn't going to be all random (even things like the CCC only _seem_ hackish).
I do help and attend spontanous meetups of all forms and fashions as well - still, they all have rules and they are all better for it.
I just say all this sounds more like "conference" (= prof) than "hacker space" (= hobby)
Both can be fun.
I'm from Stuttgart and going to the Shack is a whole different experience than going to any meetup or conference.