0 A.D. is a free, open-source, cross-platform real-time strategy game.
GLScene Engine for Delphi & C++Builder VCL Windows 32/64
CIRT - CUDA Interactive Ray Tracer
Interactive geometry software for Euclidean and non-Euclidean spaces
Logic modeling environment
3D-Accelerated open-source DOOM engine
A planetarium software that shows a 3D simulation of the night sky
GPU Fragment Shaders Repository - GLSL
Photo editing tool for Symbian (especially Pureview 808)
SDL/OpenGL/OpenCL based particle simulation.
realtime 3d surface rendering library
Java 2D graphics/utility library
simple 3d scene viewer for windows/linux/android
Opensource RTS game
Pear3DEngine is a modern and modular 3D development framework
A generalization of Conway's Game of Life
true 3D Labyrinths - generating, rendering, exploring, building
In-flight navigation (and more) for private pilots (Linux).