I caught a really interesting story on NPR about a guy from the Ukraine who takes popular songs and inverts the sound either from minor to major key and vice versa. While you still recognize the songs, the feeling completely changes. Somber songs become uplifting and uplifting songs sound somber. Some of the reworks I've heard really make me cringe but others sound pretty damn good. Check out his YouTube channel for all of his tracks. A few of my favorites are below.