As a parent having tried everything I can find (logo, scratch, hackety hack, invent with python, straight PHP programming etc. etc.) to teach my kids (currently 9 & 6) programming, the #1 problem is the medium is wrong: sitting still in front of a computer for more than 15 minutes is diametrically opposed to their natural behaviour.
The best approach I've found, which also makes a great party game is "How to train your robot" -> http://drtechniko.com/2012/04/09/how-to-train-your-robot/ . It works well because there are no computers involved.
Cargobot on the iPad also works pretty well, although largely because it's an iPad
Also recently had success with http://popapp.in plus UI stencils although this is more design / hypermedia than programming
Plus, students all get access to and personalized help from tutors whenever they ask a question or submit their code.