Just back from a day at Bar Camp which was quickly put together as a tongue-in-cheek response to Tim O'Reilly's Foo Camp and folks who had not been invited. Foo Camp is great fun, and Tim does it all for free, so it's not suprising he has to turn people away -- even me :-) -- but Bar Camp was surprisingly good for something thrown together at the last minute with no costs.
It makes you wonder why some conferences have to cost so much. In Foo Camp, Tim provides his campus of course, which he already owns, and some rental facilities and most expensively, food, and lets people come free. Programming is ad-hoc, in recognition that at so many conferences, people come not because of the program but because of their fellow attendees. I haven't asked Tim what it costs him per attendee but I suspect it's much more modest than the fees at comparable conferences. People literally camp in empty cubicles and offices, though those not up for that can get hotel rooms or bring RVs.
Bar camp was even cheaper. Socialtext provided the office space in downtown Palo Alto. In just a short time, sponsors such as Technoratti and others provided all the food people could want, and attendees brought snacks and drinks. Fewer folks camped because it was in Silicon Valley, but some of the younger set did. Talks were quickly put together, but interesting, and covered whole ranges of new and interesting software developments. And as at Foo Camp and everywhere else, hallway conversation was the real action.
With the glut of office space in this valley, and in other places, such ad-hoc conferences should not be hard to set up. Nor should sponsors be hard to find for modest food and other needs. If people become interested in having a conference rather than a business, they can do for nothing what could cost $1000 per person and with less work.
Not that I wouldn't enjoy going back to Foo Camp, but Bar was its own rewarding experience too.