Nearing the end of the OpenCamp event, we discussed the future of OpenEverything and related events. I suggest(ed) that we must first appeal to the most common attitude of most people in order to bring awareness of the benefits of openness in our society.
For example, most people are oriented toward consuming media and acquiring 'things'. If one would like to promote openness in media, create an event in which people are invited to download music/video that is licensed under creative commons.
You set up computers and projectors and speakers in a highly trafficked room to let people play media and allow them to plug in their own storage to download it. People get to fill up their CDs and thumb drives with tons of free music and movies all legally and free. Make sure some impressive music & video is playing to show bystanders that free content can be high quality.