AgentSheets / AgentCubes (http://www.agentsheets.com): Pioneering blocks environments for creating rule-based games and simulations
Alice (http://www.alice.org): Pioneering blocks environment for creating 3D virtual worlds; support for exporting to Java
Kodu (http://www.kodugamelab.com): Rule-based programming of games for xBox and PC
Looking Glass (https://lookingglass.wustl.edu): 3D animated story creation; supports independent learning