StarLogo TNG, then Python (Score 1, Informative)

Modern software is an organic soup of interacting components. To plant in your students the sense of perceiving complex system with many interacting components, I would start with the great StarLogo TNG software, which allows children to program 3D simulations & games, almost without any training. After that, I would recommend the best programming language out there (IMHO of course), Python, which is easy to learn, built on good OOP principles & powerful for any task at hand. For letting your students really use what they've learned, teach them also Web development, e.g., with Django, & teach them how to deploy Web applications to the Google AppEngine cloud. By experimenting with this & building useful stuff that is available for all, they'll truly learn what's programming all about.