Virtual world platforms such as "Second Life" have been successfully used in educational contexts to motivate and engage learners. This article reports on an exploratory workshop involving a group of high school students using "Second Life" for an urban planning project. Young people are traditionally an under-represented demographic when it comes to participating in urban planning and decision-making processes. The research team developed activities that combined technology with a constructivist approach to learning. Real-world experiences and purposes ensured that the workshop enabled students to see the relevance of their learning. Our design also ensured that play remained an important part of the learning. By conceiving of the workshop as a "serious playground", we investigated the ludic potential of learning in a virtual world. (Contains 1 table and 8 figures.)