In Our Time is a podcast from the BBC about the history of ideas presented by Melvin Bragg or to be formal Lord Bragg of Wigton. The other presenters are usually academics from various British institutions with a speciality in the area being discussed.
The topic and guest presenters will be introduced by Melvin Bragg who will then act as a moderator and interested layperson with the discussion between the academics. This usually produces a clear and interesting discussion of the idea being featured. I have heard shows about probability, the Arab Conquests, the Riddle of the Sands and Lysenko. The themes from the BBC's website are Science, Religion, Philosophy, History and Culture.
There is an archive, but it only allows streamed content to be accessed rather than downloaded and only the latest weeks podcast can be downloaded from iTunes or other aggregation sites.
The audio quality is excellent which is not really surprising with a podcast from a major broadcast organisation. Streaming from the BBC website or downloads via iTunes are reliable and quick
I do like this podcast a lot as it is interesting and very good at explaining complex issues. Highly recommended, though it hardly needs my endorsement to be successful.