portable C++ GUI library designed for games using Allegro, SDL and/or OpenGL, comes with a standard set of widgets and can use several different backends for displaying graphics and grabbing user input
a 2D fighting game in the same style as Double Dragon and TMNT. Paintown is very extensible and comes with editors to help design new levels and animations.
a 3D Collision Detection and Rigid Body Dynamics Library for games and animation. It is an Open Source multiplatform C++ project. Discrete and continuous collision detection, integrated into Blender 3D and COLLADA 1.4 Physics tools support.