The Blue Shell Blues song on Ninendo UK's Youtube channel. If they cut the song into 30 second bits and had them in the background of a video with gameplay clips of characters getting hit by blue shells in slow motion and people angrily flipping out (muted) with their friends in slow motion, it would be perfect.
Nintendo needs to capitalize on the fact that 99% of the fun in Mario Kart for most people comes from how it makes you hate your friends. Put that feeling together with a catchy song like this one so that it stays in people's minds. Once they have the song stuck in their heads, they'll constantly be thinking about their fun times with Mario Kart.
I still stick by my belief that one of the PS4's biggest sellers was that "It's such a perfect day" ad. It's such a perfect commercial. (pun intended) Music connects with people in a way that "clever" ads just can't do alone.
Here's the video: https://www.youtube.com/watch?v=4T3cAyfIBmw
