Scrimba is $19/month, and aimed at adults. From the front page, you build boring stuff, and it's not clear where to go. Quality is mixed
For general coding for kids, there's a bunch of really excellent things:
* Khan Academy JavaScript is fantastic. You learn JavaScript building interesting things, learning both deep and shallow concepts.
* code.org tends to be an hour long, but that hour is beautifully scripted. It doesn't go far, but is really nice for getting started.
Scratch, Blockly Games, Open Processing, and a bunch of others do a nice job picking up from there.
Where there is a gap is on tying code to hardware, which this starts to close. What I liked about this is you start with something physical. This isn't just coding. It's coding+electronics. It's surprisingly hard to find good stuff for RPi, Arduino, or similar. There are:
* Great robotics platforms, without software support or tutorials
* Decent software, where there is a game of making it work with pick-your-own-hardware.
* Decent tutorials, bogged down by lousy platforms, no integrated way to get the stuff you need, etc.
* Etc.
There isn't anything clear, integrated, and coherent like the ones above (KA/Scratch/etc.) that I know of.
If someone were to take a:
* best-of-breed cheap kid-friendly robotics platform
* integrate it with arduino or rpi
* integrate it with JavaScript or Python
And have a 5-minutes-to-get-started thing, and from there, ways to go deep, it'd be a pretty big hit. No organization seems to do all three pieces well:
* Hardware
* Software
* Pedagogy
Perhaps since they're such different skills, or perhaps because it's too big a task.