This paper uses Australian case studies to demonstrate the use of humour in social justice and eco-pax 1 movements. Drawing from the literature and from personal experience in activist street-theatre over more than twenty years, the author discusses the rationale and motivations behind humorous activism, and notes audience reactions and impacts on participants. Using non-violence theory within the multidisciplinary paradigm of Peace Studies, he describes how activists use humour to enliven popular education, and to create liminal atmospheres conducive to non-violent conversion. Humorous activism creates common ground and complements other modes of activism. It is inclusive, drawing in audiences and adherents and attracting media attention. It simplifies and enhances communication, and allows activists to release emotions such as rage and frustration, while at the same time providing positive, enjoyable experiences for audiences. It can empower and inspire audiences, and bring a healthy balance and diversity to activism. [ABSTRACT FROM AUTHOR]