This article situates contemporary forms of video activism in online environments within a historical trajectory of radical film recruited for Left thinking and action. Focusing on the remix ethos and aesthetics of political mash-up videos, the article suggests how revisiting the analogue precursors of digital video may help contextualise and understand new forms of video activism, and politically committed media practices more generally. In the first part of the analysis, I engage with some of the principal conceptual themes and aesthetics that shape the various hybrid genres of the kind of visual activism we see emerging in YouTube and similar video platforms today. For these purposes, I propose a typology for understanding the motley array of video documentary and documentation available online as a hybrid and diverse range of media forms for political investigation and portrayal. The second part of the analysis demonstrates how such mash-up practices play out on three distinct levels when digital videos are put in circulation online. First, political mash-up is understood as a set of material practices in which online content is mixed and repurposed, second, in terms of a convergence between different styles, genres and modes of address, and finally, the concept of mash-up opens up for an understanding of the blurring of boundaries between different political actors and motives in online media environments.