In Helsinki, summer 2010, a group of friends challenged each other to just consume at local independent stores for two weeks long. This challenge became an event of public calling for controversy, rallying support for small independent shop owners, in opposition to large retail chains. This forms the premise of a case study, according which this paper will argue that the design of an event as such is not only relevant in forms of activism, but is also relevant for design in general, especially when design addresses behavior change or lifestyle change. A qualitative study based on Maffesoli���s theory of neo-tribalism identifies this event as mediated and designed. Although more study is needed, this paper suggests that an event as such fosters a certain image, celebrates certain behavior and that it entails a behavior change for those that join it. As such, it is a powerful means for design when it comes to behavior change: Designing with behavior for behavior.