An early '90s specialty show on KCOU that I had difficulty describing was "Gardening At Night." A key element of it, however, involved crafting sound collages consisting of live or recorded spoken words paired with musical backdrops.
One night, Robi, the DJ hosting the show, and I started talking, and he recorded part of our conversation. Later in the show, he asked me, "(Does this) sound familiar?"
It did sound familiar, as he had put a portion of our chat on a tape loop and was playing it on the air backwards over music.
Where else can you do that on the radio?