One way in which we can get philosophy out into the public sphere is to hold festivals that offer several events, spread over one or more days. Such events are a lot of work, but they can get big audiences. (We got hundreds of people to come along when we ran one in London in December 2011.) I make this post:
(i) to encourage any brave souls on this site to try them in their own areas;
(ii) to invite views on what works and what does not work at such events;
(iii) to let people know that we have such a festival in London on Sunday 8 September, and to invite anyone interested to come along for all or any part of the day. It is free of charge, and no booking is required. The programme is available here:
I can confirm that festivals like this work very well - although there is plenty of organization and work to do. We got several hundred people coming along. I don't know quite how many, because we did not require booking and people did not have to buy tickets, but I would guess that somewhere between 500 and 800 people may have attended for all or part of the day, with about 300 in different rooms in the building at any one time.
It is worth having a variety of types of event, so that there is something for everyone. We generally had lectures and more participatory events running in parallel.