Grit Game Engine - The Grit Game Engine is an MIT-Licensed Open Source Game Engine that is highly scriptable via Lua.
BlitzPlus - Create 2D Games for Windows.
libtwo - All-purpose c++ app prototyping library, focused towards live graphical apps and games
BlitzMax - With the developing version BlitzMax NG other 'targets' are available: ARM architecture, Raspberry, Android, HTML (Emscripten). RAPID DEVELOPMENT. Just open the IDE, write your code, hit F5 and see immediately the results!
MOS - Lightweight game engine.
Monkey 2 - An easy to use, cross platform, games oriented programming language