History Channel: The Bruneval Raid (51 min). Also covers the so called "Battle of the Beams".
Heroes and Weapons of WWII: The Men Who Invented Radar (23.5 min)
Heroes and Weapons of WWII: The Men Who Cracked Enigma (24 min)
I have always been interested in the history of Signals Intelligence, Electronic Warfare and related areas, so I really enjoyed these fine videos.