From the Wikipedia:
"Foo Camp is an annual hacker event hosted by publisher O'Reilly Media. O'Reilly describes it as "the wiki of conferences", where the program is developed by the attendees at the event, using big whiteboard schedule templates that can be rewritten or overwritten by attendees to optimize the schedule. The goal of the event is to reach out to new people who will increase the company's intelligence about new technologies, and to create opportunities for cross-pollination between people and technologies that are on the O'Reilly radar.
Some have described it as a meta-birds-of-a-feather session that gets smart people together to discuss technology issues. This style of event has also been described as an unconference.
The event started as a joke between Tim O'Reilly and Sara Winge, O'Reilly's VP of Corporate Communications. Sara had always wanted to run a foo bar, an open bar for Friends of O'Reilly, at one of O'Reilly's conferences. That joke morphed into a brainstorm after the dot com bust left O'Reilly with lots of unused office space in its new buildings, creating the opportunity for Foo Camp. There was eventually a Foo Bar at the camp.
Tim O'Reilly describes the goal of his company as "changing the world by spreading the knowledge of innovators." Foo Camp has evolved into an important mechanism for finding those innovators. O'Reilly asks attendees to nominate new and interesting people to be invited to future camps. The invite list is calculated to create cross-disciplinary "aha!" moments, new synapses in the global brain, with a focus on emerging technology." (http://en.wikipedia.org/wiki/Foo_Camp)