Grassroots initiatives enable communities of stakeholders to transform urban landscapes and impact broader political and cultural trajectories. In this two-day workshop, we present opportunities to engage HCI research with activist communities in Vancouver, the city hosting CHI'11. Working directly with local activist organizations, we explore the processes, materials, challenges, and goals of grassroots communities. Our bottom-up approach, including explorations of urban spaces and activist headquarters, participatory design sessions, reflection, critique and creative design of political artifacts will bring together a diverse group of HCI researchers, activists and artists. The workshop will result in concrete strategies for bottom-up activism and serve to inform the design of future interactive systems in the domain of political computing.