If hardware isn't a requirement, I'd point you at processing.org and the various related projects (openprocessing.org for a javascript front end.). It hits that

If hardware isn't a requirement, I'd point you at processing.org and the various related projects (openprocessing.org for a javascript front end.). It hits that logo sweet spot for me when introducing kids to actual programming. Then, add a pen plotter to the mix for that "look what I made" kick.