Thanks go to Jenny for the link to the They Might Be Giants podcast!
And all that brings up something I was too lazy to figure out before. Interestingly, it became an issue now only because I was also too lazy to look for the TMBG podcast in the iTunes podcast directory. It turned out to be easy enough to subscribe directly, but here are the directions from Apple:
If you can’t find a podcast on the iTunes Music Store, never fear. You can subscribe to virtually any podcast in the known universe by dragging its URL into your podcast playlist, or by typing the URL into “Subscribe to Podcast” under the Advanced menu.
So there you go. No more excuses.