Perhaps this is old news to many, but I was excited yesterday to discover that one can hear the only known recording of CSL giving a broadcast talk -- the WWII-era radio talks that were later written up as three small books and then welded into Mere Christianity -- on the BBC's website:
The BBC states,
"This is the only surviving footage of C.S. Lewis's broadcast talks. The New Men is the last episode in Beyond Personality, the third series. It was broadcast on BBC radio on 21st March 1944."
The site also has 1:57 min of Lewis talking about The Great Divorce.