"Stuff You Should Know" podcast. It's a frequently updated show where two host discuss a topic in a casual way. The topics in th past have inlcuded sleep, Masons, crime scene cleanup, venom, prison, rehab, and more. Sometimes the 30 minute podcast is only enough for a surface look, and other times they go into greater detail. The discussions feel like the hosts only just learned about their topic in the last few days, which makes it more accessible.
With the recent protests we've seen in Seattle (which were really mild) and with riots around the world (much more serious) getting press, the question of riot control comes up quite a bit.
I found the Stuff You Should Know podcast on riot control fascinating. They discuss what causes riots and how modern policing practice are designed to end riots with minimal injuries. I found the discussion of tactical units advancing on rioters particularly interesting.
Each podcast has an accompanying article on the How Stuff Works website. The article covers most of what is on the podcast, but inlcudes more diagrams and resources. This one is worth reading.
I'd link to the particular episode of the podcast, but I can't seem to find a program list on the website. You should be able to find it on iTunes or your favorite podcast agregator. The home page for the show itself is here.