For four years a robotics festival has taken place at the Ecole Polytechnique Fédérale de Lausanne (EPFL), in Switzerland. As the number of visitors has rapidly grown from a few thousands to a dozen thousands, it gives an opportunity to investigate who is attending this event and which impact can be obtained in terms of education and motivation toward understanding science and technology. In the 2011 edition of the festival, a large survey was carried out, collecting data from 3423 visitors. The analysis of the collected data gives an idea about the profile of the people attending the event and the key factors impacting the acceptance of science and technology. Findings show that people of all ages and especially children and families have been attracted. More men than women attended the festival and visitors tended to have completed higher education. Overall, people appreciated that the event gave them the opportunity to make themselves a picture of robotics and some teenagers got encouraged to learn more about it. We conclude by presenting our lessons learned and make suggestions to help others with organizing public robotic events.