Rarity is not happy. (Check the cover if you don't know what I mean.)

(If you're too lazy: http://twitter.com/AS_PlusMinus/status/364103159670910976 )

Buy on Bandcamp: https://jackgraysonfox.bandcamp.com/track/rariwhat-instrumental-edit
Download (Equestrian Beats): http://eqbeats.org/track/8511
Download (Pony.fm): http://pony.fm/t2583
SoundCloud: http://soundcloud.com/jackgraysonfox/rariwhat-inst

I cut out all the samples because, you know, copyright. (It took a bit of work since I lost all the source files a while back.) Also, I made a new cover, which doesn't copy anything from the show. (Names can't be copyrighted.)

This song (along with its cover) is available under the Reciprocal Noncommercial-Free License: http://halfgray.tk/licenses/reciprocal_noncommercial-free_license 
Basically, that means you can use it for any purpose, even for commercial purposes. But, you have to share your creation under the same license (or a Creative Commons Attribution-ShareAlike license), and of course credit me. It's free as in freedom.
There are some flexibilities for noncommercial use and other things; check the link for details.