Pygrid is an open-source and cross-platform pygame/python 2D engine.
Kinect based controller.
A 3D, fully concurrent game engine
This pack add's custom object and rides into your "RCT3 Platinum" game
A game development kit for Sifteo Cubes.
Extremely simple joystick rumble / vibration library
3D game engine for C and C++
A graphics engine + toolkit.
Hungry Hero is an open source Flash game built on Starling Framework.
Sprite Font Creator
Create your own animated characters for games with ease!
Allows the Sourcemod FunCommands to be limited
3D Web UI, Embed Web and Flash in 3D Games, based on WebKit
Pear3DEngine is a modern and modular 3D development framework
Phobos editor is a generic resource editing system.
Open Source Virtual World and MMOG Development Platform
QuadTree JS is a library for game developers
cross-platform 2d game engine
Powerful html5 & javascript library for creating applications & games.
Cross-platform reimplementation of AMOS BASIC (runtime)
Fully fledged steam community SDK