Microsoft’s Project Spark is a game or world creator for Microsoft Windows 8.1 and Xbox One. An Xbox Live account is needed to download and use Project Spark. This can be obtained free and linked to any Microsoft Account. See Wikipedia article. This blog post brings together links and resources during a quick test.
Project Spark – Resources
Project Spark – Create, Sculpt, Share, Play
Suspension Platform Game Example
Champions Quest: Void Storm Game Example
Project Spark – World Creation Tools
Project Spark – AiLand Test World