For those that don't know, there are some multitracks floating around the internet of Marvin Gaye and Van Halen (as well as Queen and the Beatles and more, I'm sure). Basically, you can download mp3s of the individual tracks that make up the song (drums, bass, guitar, vocals, etc.) and remix them yourself. So this guy put Gaye and Roth together.
I think he could've used some pitch-shifting on Roth to get him more in tune with the key of the music. I give him a B+ for the idea, but a D for the delivery.