Programming for kids

So how much programming can a six year old learn? OK, it's not exactly a scientific question nor do I intend to conduct this scientifically, but I think it would be interesting to see just how much of a basic understanding of programming a six year old can learn and be interested in. I know there are plenty of programming languages for kids, but I'm more interested in seeing how easy or hard the concepts of a mature mainstream language are.

So what I'd like to do is try this with Python and/or Ruby. Of course there are some extra benefits over and above actually learning to program, in that essential skills are also learning to read, type and spell. Compilers and interpreters are somewhat less forgiving than us humans in reading a typo. (hmm now there's an idea - I wonder if anyone has ever implemented a Levenshtein distance formula into a compiler/interpreter to cope with minor typos.)

So I hope to be able to make this a multi-part series of posts tracking our progress. Naturally if he shows zero interest it could be the shortest series of blog posts in the history of the internet. And I wouldn't want to be accused of experimenting on my children either. :)