This is how I explained open space recently to support a partner explaining to their board what it was:
Open Space Technology is an energizing and emergent way to organize an agenda for a conference. Those coming to the event can post on a wiki ahead of time topics they want to present about or hope others will present about. The wiki can also be used to share who is coming because we know great people who will be there and it is the attendees who have a passion to learn and contribute to the event that will make it.
The event begins with face to face schedule making which allows for emerging developments in this rapidly moving field to be covered. The opening includes time for attendees introduce themselves and orient to the whole group. Participants are then invited to come to the front of the room and write the name of there session topic and their name on a 8.5Ã—11 paper. They announce the title of their session to the whole room and then post it on a schedule on the wall. Then once all the sessions have been posted the community standing in front of the schedule wall attendee move sessions around. Sessions are about an hour long with 15 min breaks and an hour for lunch. The day closes with the all participants gathering in a circle one room and sharing for 20 -30 min the highlights of the day.