Bret Victor (Inventing on Principle) wrote an excellent essay on Learnable Programming. If you have any interest in how people learn computer programming best, or how people learn in general, then go read it. Now. Shoo. And you probably want to read it on a computer; there are several short videos to accompany the text.
This essay was an immune response, triggered by hearing too many times that Inventing on Principle was “about live coding”, and seeing too many attempts to “teach programming” by adorning a JavaScript editor with badges and mascots.
The gauntlet has been thrown down for the Khan Academy CS program. They just got served.