I'm a developer at Khan Academy (currently working on the upcoming Android app), and it's cool to see that there's real interest in that kind of use case! In our hackathon a few weeks ago I wrote an audio-only Khan Academy app that lets you listen to any video or the text-to-speech of any article and is controlled completely through voice commands. Unfortunately it's not quite at a point where other people can use it, but maybe I'll take the time to actually productionize it. :-)
That's great, thanks for posting it. And I love Khan academy, thanks for the great work. My son is 3 and I'm chomping at the bit to introduce him to Khan academy.
Interesting I've been doing podcasts during my drives but never thought about Khan Academy. You can get away with not seeing anything they put on the screen or draw on a whiteboard? Have you had success with just listening to all the courses?
There are lots of websites that will extract mp3s from youtube videos which you'll find if you just google "youtube to mp3". There are also browser extensions which do this. Here's one:
Here's the code if you're curious:
https://github.com/alangpierce/Audicademy
And there's a feature-incomplete web version that lets you navigate to any video and play it (requires a recent version of Chrome):
https://audicademy.appspot.com