Comment Env3D (Score 1) 237
The Env3D engine (http://env3d.org) is an open-source education focused 3d engine. It is made for learning Java at the first year university level, but has been successfully used in high schools as well. Since it is focused on education, it abstracts away many of the technical details of traditional 3d engines. It currently creates web applets and applications that run on PCs (windows, osx, and linux), but the plan is to have applications deploy on andriod also in the near future.
Full lessons and demo programs can be found on the env3d website.