What can we learn about civil society in Central and Eastern Europe (CEE) and Russia from studies on activism within the region’s urban spaces? In this article, we argue that studying urban activism in CEE offers useful insights for general theory building about the importance of uneventful protests, the formation of agency and the processes of becoming active in the public sphere (conceptualized here as “political becoming”), and the enabling role of informality in collective action in adverse contexts. By contributing to our understanding in this way, these insights help to advance relational and process-based conceptions of civil society.