The conference theme for the tenth Participatory Design Conference, PDC 2008, is Experiences and Challenges, honoring two decades of biannual PDCs. The research papers and other contributions reflect on past experiences and review the important lessons we have learned so as to better meet the new challenges of the future: What are the important trends, phenomena, developments, and views on participation and design etc., which in so many different ways challenge our traditions, our experiences and/or the current 'wisdom' within the field?