Pygame - Pygame is a set of Python modules designed for writing games.
Godot Engine - Feature-packed 2D and 3D open source game engine.
MonoGame - MonoGame is an open source implementation of the Microsoft XNA 4 Framework.
DragonRuby Game Toolkit - DragonRuby Game Toolkit is a commercial-grade, yet beginner-friendly, 2D game engine.
RPG Maker - Make your own PC game with RPG Maker. Our easy to use tools are simple enough for a child, and powerful enough for a developer. Try it free today!
Unity - The multiplatform game creation tools for everyone.