The mobile internet provides new and easier ways for people to organise themselves, raise issues, take action, and interact with their city. However, lack of information or motivation often prevents citizens from regularly contributing to the common good. In this paper, we present DoGood, a mobile app that aims at motivating citizens to join civic activities in their local community. Our study asks to what extent gamification can motivate users to participate in civic activities. The term civic activity is not (...) yet well defined, so we collect activities citizens consider to be civic to work towards a broadly accepted definition of the term. The DoGood app uses gamified elements that we studied to gauge their role in encouraging citizens to submit and promote their civic activities as well as to join the activities of others. DoGood was implemented and deployed to citizens in a five-week-long user study. The app succeeded in motivating most of its users to do more civic activities, and its gamified elements were well received. (shrink)