Create a private podcast feed

I’ve gotten into the habit of listening to spoken podcasts at a reasonably high speed using Smart Speed in Overcast. I’ve a few directories of sound files I’d like to listen to in Overcast, but that Overcast can’t directly import from an existing RSS feed, e.g.:

• Some of these are available by RSS, but are from a subscription-only site who’s security doesn’t play nicely with Overcast’s feed crawler.
• Some are ripped from CD’s.
• Some are podcasts I grabbed some time ago, but which have now disappeared from the internet because their host sites only keep the most recent few episodes available.

I needed a way to create a private RSS feed available only to myself, or at least not publicly available out to the whole wide world.

Listening to episode 10 of Cortex I heard several suggestions. The best & simplest of which involves a simple Ruby script to process a directory in Dropbox: