del.icio.us helped me stumble onto Crystal Space 3D. Check it out if you fancy yourself to be some kind of "software developer" who wants to make games.

Crystal Space is a free (LGPL) and portable 3D Game Development Kit written in C++. It supports: true six degrees of freedom, colored lighting, mipmapping, portals, mirrors, alpha transparency, reflective surfaces, 3D sprites (frame basedor with skeletal animation), procedural textures, particle systems,halos, volumetric fog, scripting (using Python or other languages), 16-bit and 32-bit display support, OpenGL, and software renderer, font support, hierarchical transformations, ... See the extensive list of features for more details.