This post is a wiki so you can edit this directly.
Put your favorite picks here. This came from a lunchtime GOAT discussion which seemed very productive.
The History of English Podcast - http://historyofenglishpodcast.com/feed/podcast/
Revolutions podcast - http://www.revolutionspodcast.com/
The History of Rome - http://historyofrome.libsyn.com/rss
Gadgets Podcast https://www.embedded.fm/
Linux Podcast http://www.jupiterbroadcasting.com/show/linuxun/
Farming Podcasts http://www.farmertofarmerpodcast.com/ & http://www.theruminant.ca/
Culture Podcats http://www.zero-books.net/ & http://www.globalagogo.com/
A closed and common orbit - Becky Chambers