This paper investigates how the merging of social interaction and gameplay can enhance learning practices. By drawing on the theory of situated learning (Lave and Wenger, 1991), and by using social network games as case studies, I reflect on the potential of multi-player collaborative play to promote learning. I argue that the simple game mechanics and the collaboration-based gameplay of social network games transform them into a unique space for promoting not only the simulation of real-world experiences and the active engagement with problem solving, but also the building of a social environment that is highly beneficial for learning. To develop this argument, I look firstly at the main approaches adopted in studies of games and learning, summarising the forms of individual learning that are usually related to videogame play. Then, I explain how social network games have shifted the emphasis from individual to social learning, and why the theory of situated learning can be fruitful in analysing serious social play. As the final step, I use the Facebook games EcoCity and Trash Tycoon to discuss social network games from the perspective of situated learning, offering a new understanding of the role of social interaction and collaboration in serious play. Although this investigation is primarily theoretical, the analysis of those games shows that, by playing them, individuals can effectively learn about sustainable development and environmental issues.