The chapter discusses a certain type of activism and cinema associated with it, which cannot be described as strictly ‘Marxist’, but which might appeal to Marxist viewers: the Critical Mass movement. This movement, which started in the early 1990s, consists of groups of bicyclists riding through inner cities in numerous countries. The Critical Massmovement can be assessed in two basic ways: either as a means of combating capitalism by challenging the domination of a private car in the cities and advocating living in a more sustainable and greener way, or as a one-issue activismthat diverts attention from the crucial problem of capitalism, which is that of class. The chapter also discusses the films that represent and advocate bikeactivism and living according to the ‘bike ethos’ in terms of their production, textual characteristics and distribution. It draws attention to the fact that cinema is crucial for bike activism and the internet is indispensable for Mass Movement cinema.