Attended one sometime back. What hit me was that they didn't even bother to bring water and they remembered when I needed some. Needless to say there was pizza(and the way it was spread around was "yuck"), there was soft drink and beer and there was no water; neither any fruit or even trace of some healthy food or just food.

Nothing new or innovative came out other than sore backs, necks and a guy puking. Yes, there were some 'nice' hacks like "this guy build this using that hooking into that that API and showing this again".

Midway, I felt like sleeping - there wasn't any space and I was sort of looked down upon with scorn - as in "he doesn't belong here". Well, I didn't. I had built a little web app that did some basic(very) search with Tw/Fb. Nth I would like to see or ponder over again. I slept in a corner anyway(had my sleeping bag).

Bad thing it wasn't fun either.

Moral of the story - it's good for sort of a meet-up, not for 'breaking the ground' with your ideas :-)

And if you have to organize one - make sure there's food, water and some place to rest. Proper lighting which can be adjusted in different corners/parts of the hall(or the large room).

PS. And yes, keep it spacious and airy. Man is a messy animal :-\