This song. It's a mashup by Oli Clifford, the music is Arctic Monkey's "Mardy Bum", and the female vocals are Destiny's Child's "Lose My Breath." I'd never heard of the guy before. This track was a bonus on the Mashup best-of 2006 album, which I heard about in a BoingBoing post.
This is one of the things I love about mashups. Every once in a while, you get a song that is significantly better than the originals. It's subjective of course, but to my ear the mashup is loads better. The Arctic Monkeys song isn't bad, I like it OK on its own, but it's not remarkable. The Destiny's Child song is totally forgettable. If you listen to the vocals in the mashup, they're good. But for their own cut, they randomly pressed the buttons on a drum machine for the "music." If you're curious, you can hear a snippet of each song on iTunes.
The resulting song is really good. Great guitars and bass line on the music, the vocals over this music are 50's girl-group doo-wop. I can picture the beehive hairdos and synchronized dancing.