BBC Radio 4 has a variety of extremely well-done (with professional actors) podcast "mini-series." You might want to check out the first 7 episodes (out of 10), 15 minutes each, of the one in progress now—a fascinating and witty series by Dr. Geoff Bunn on THE HISTORY OF THE BRAIN.
1. A Hole in the Head
2. The Blood of the Gladiators
3. The Origin of Common Sense
4. Spirits in the Material World
5. The Spark of Being
6. The Beast Within
7. Mind the Gap
