Richard Darst has been writing about DebConf organisation and wrote about DebCamp. Thought I'd give my story about where the idea for DebCamp came from, for some context.
DebConf2 in Toronto was my first DebConf. I had sadly missed DebConf1 due to EPASSPORT despite having sponsored tickets; something I still kick myself about. Things were not as well organised back then. Anyway, since Ottowa Linux Symposium was the week before DebConf, some of us were in Canada early for that, and needed to find something to do in the time between conferences.
My thought was, find someplace to camp. It'd be a cheap way to see more of Canada and decompress. I posted this plan to debian-private and Andreas Schuldei and I spent several days canoing around Algonquin park. Of course, we'd never met before. I'd met probably less than five European debian developers before that point. We experienced big scary lakes that challenged our limited canoe skills, portaged and camped, and even saw a moose.
Later during DebConf2, I distinctly remember mentioning our camping trip and saying "we could have a DebCamp before the next DebConf". And sure enough, before DebConf3 there was a DebCamp. In the days we hacked on d-i and stuff. We camped out in the gym of a primary school in Oslo, and hung out through the long evenings out front. Some people even brought tents.
Since then, DebCamp has developed into the integral warmup for DebConf that Richard describes. I'd rather see it more ad-hoc and scruffy, but you can't argue with the purpose it serves.
So, are there any good places to camp near Banja Luka?
 Even then the DebConf orga team made it seem that easy.