Kodu
Kodu is a visual programming language specially designed for creating games. User can create their own 3d worlds, objects and characters which are programmed using a simple icon-based language. The language includes typical game scenarios so it's relatively straightforward to make a simple game.
http://www.kodugamelab.com/About
http://www.youtube.com/watch?v=xXfovBy1LTA
https://www.tes.com/teaching-resources
Video tutorials http://www.youtube.com/consolarium
Kodu Manual - https://docs.google.com/open?id=0BwiY2xYzjHIYc3VJcnd2NGpfVU0
Kodu Help Sheets - https://docs.google.com/open?id=0BwiY2xYzjHIYbkVRZmJRQ0VRQVk
Kodu KS3 SOW - http://www.interactiveclassroom.net/?page_id=189