Alternative Cultural Places (ACPs) face unique challenges related to sustainability. Through a series of collaborative workshops, the members of the Alter-Places consortium explored these complex issues by using prototypes as tools to test solutions. Our approach is rooted in an iterative, experimental, and flexible process, inspired by art-based methods. Each prototype was designed to address a specific problem while also being a solution that can be replicated by other ACPs. By acting as an international lab for dialogue and experimentation, Alter-Places aims to reinvent ACPs as spaces for alternative ways of living, creating, and working. The four workshops that structured the project were key moments for collective reflection, production, and testing. Below, you will find all the prototypes produced, the methods used to develop them, as well as templates that can be adapted by other interested ACPs.