Keskustelupuisto - Conversation Park describes a unique artistic experiment of transforming an abandoned plot of land into a public park in the Finnish town of Rauma. In 2019 thirty residents between the ages of 6 and 89 became players in a two-year-long "Public Space Game". Their mission was to turn 30 different personal visions into an attractive urban park in 6 game moves. The park was opened in 2020 and has been already nicknamed "the green living room of the town". The creators of the project - artist duo Tellervo Kalleinen & Oliver Kochta-Kalleinen - describe their original intentions when designing the game and share insights they gained while working on Keskustelupuisto for 4 years. The book touches on many important questions with regards to engaging citizens in designing urban public spaces. It is an attempt to open-source the Conversation Park project so that it can be analysed, modified, and replicated. It is an invitation to learn together with the artists and the participants about the many factors which have to be considered when designing a participatory project - whether it takes place in art, urban planning or politics.