Freya 3D engine is a cross-platform, modular game engine with OpenGL backend (and possibility to add a Direct3D one), heavy integration with Lua (using LuaJit as VM).
The engine is currently on fairly early development stage. We truly sick for C++/Lua developers, designers, modelers etc.
... [More] Currently, the main developers language is Russian, yet this can be easily changed to English. [Less]