I just recently discovered this and I don't think it's very well-known. A Socialist organization in the UK has put literally hundreds of lectures online for free mp3 download.
Most of them have something in some way to do with socialism or Marxism, but even if that's not your thing, there are history lectures and current affairs lectures from a leftist perspective that anyone here on DailyKos will like.
Fans of Chomsky (I'm not one myself) will see that there are lots of his mp3s there and fans of Howard Zinn (also not me) will appreciate the complete People's History of the United States audiobook there for free as well.
http://mp3.lpi.org.uk/...
My personal recommendation is the lectures by Mark Steel. He's normally a comedian, not an academic, so his lectures are very funny and entertaining and will give you a completely new perspective on Karl Marx, the Russian Revolution and the French Revolution.
Others I've listened to and enjoyed so far- The Peasants' Revolt of 1381 and Robin Hood: Myth and Reality.
Anyway, I think many Kossacks will enjoy the vast selection of free lectures I discovered, so... um... enjoy!