Scratch - Scratch is the programming language & online community where young people create stories, games, & animations.
Blockly - Blockly is a library for building visual programming editors.
EduBlocks - Making the Transition from Scratch to Python easier.
Playir - Create your own mobile apps & 3D multiplayer games with our super-easy design tools for iOS, Android, Windows Phone and HTML5! Less programming, more playing.
Snap - Snap (formerly BYOB) is a visual, drag-and-drop programming language.
Unity - The multiplatform game creation tools for everyone.