Castle Game Engine - An open-source 3D/2D game engine for ObjectPascal.
Blitz3D - Create 2D and 3D Games for Windows.
Cyberix3D - Free online 3D Game Maker. Make your own 3D games online!
BlitzPlus - Create 2D Games for Windows.
Open 3D Engine - Open 3D Engine is an open-source 3D game development engine in real-time.
Monkey 2 - An easy to use, cross platform, games oriented programming language