I've started listening to podcasts as I ride: the ear bud headphones that I'm using, plus the fact that my iPod is loaded only with spoken word stuff rather than music, together don't seem to be affecting my ability to hear what else is going on around me.
After 18 hours of Charlie Rose interviews, next in the queue was about 150 public lectures on various topics given at Stanford.
I've already developed some rules of thumb to help me figure out early on in a lecture whether I should cut my losses and skip ahead to the next one:
If the speaker uses the word "narrative" and the word "discourse" within 30 seconds of each other.
If the speaker uses the word "meta-narrative" even once. Seriously, one strike and you're out :)
All joking aside, it's possible to listen to stuff like this, enjoy the fact that it sounds smart or that you feel smart for listening to it, and only at the end realize that the talk had so little connection to the real world that you in fact learned absolutely nothing :)