I wanted to listen to the excellent Structure and Interpretation of Computer Programs lectures on my way to work, but they're all in MP4 format - i.e., video with audio. To extract the audio was a mere one-liner in Ruby:
Of course, all the real work is done by
lame, but, still!
After listening to the first couple of lectures I'm not sure exactly how much I'm getting out of the audio-only version; there's a lot of chalk-on-blackboard noise and code examples that I can't see. But the instructor commentary is interesting nonetheless, and it sure beats talk radio.