Finished a project with some students at the school i work using VRML/X3D as a constructivist learning tool. They designed and built a virtual world about biological structures. You can read about the project here: 3D Alpha Viagem de um Glóbulo Vermelho in portuguese. As soon as i can i will embed some X3D files related to the project and put the virtual world online at VRMLWorld. You can view here some of the x3d files: 3D Alpha Modelos Virtuais X3D.