Project Wonderland is a toolkit for building 3D virtual worlds. The platform supports immersive audio, 2D and 3D shared applications, multi-user Java programs in 2D or 3D, and telephony integration. The environment, built on the Project Darkstar game server infrastructure, is open and extensible, allowing developers to create highly customized virtual worlds of all different types. In this session, we will show a number of different virtual worlds built by members of the Project Wonderland open source community members. Each highlights different aspects of the Wonderland platform and the wide range of possibilities open to developers.