Everything Little Thing
This is hands-down my favorite podcast—and trust that I listen to lots and lots of them. Host Flora Lichtman creates such a compelling and entertaining storyline no matter the subject. The most recent is about that haunting, almost indescribable scary sound that was used in Unsolved Mysteries.
I think you should listen to all of them, but if you want just a taste, one of my favorites (and the first I heard) investigates how old Winnie the Pooh is.