IvoryBrony recently created two mashups, and they are absolutely magical.
The first is a combination of Owl City's Good Time, Zedd's Spectrum, and The Type of Pony Everypony Should Know. The second mixes Gaga's Highway Unicorn Road to Love and Strange New World (from Equestria Girls).
IvoryBrony weaves all of this music together in a truly beautiful way. Give them a listen! (I would also encourage doing a little dance.)