I took Robocode[1], made a basic Robot class that the kids could easily extend, and then taught them just enough logic and syntax so they could have their robots battle their classmates'.
It was a huge success. We had to close the door to the classroom because the kids were so loud, cheering their robots on.
Whenever a kid was called by the teacher to do their one-on-one, they protested "one more minute, I need to improve my robot!"
In September, my daughter starts university in software engineering; mission accomplished! ;)