Beta Release 0.13r009 of the Crystal Space Free 3D Engine is now available (thanks Billy "Crystal" Wilson). Here's the lowdown from the site on what this engine does:

Crystal Space is a free (LGPL) and portable 3D engine written in C++. It supports true 6DOF, colored lights, mipmapping, portals, mirrors, alpha transparency, reflecting surfaces, 3D sprites, scripting, 8-bit, 16-bit, and 32-bit display support, Direct3D hardware acceleration on Windows, Glide and OpenGL hardware acceleration on Windows and Linux, ... See the extensive list of features for more details.