I played with Scratch for some time with my 9 year old son. They've done an excellent job with it. We ended up using Construct 2, only because they've done an even better job and it releases to HTML 5, is playable on all kinds of devices including iPad.
Edit: looks like it's Windows only. Will try with WINE.
Edit2: Pretty buggy on WINE over Kubuntu 14.04 - crashes when trying to start project from template or when run layout on empty project.