I dunno if anyone posted this before, but I've been pretty much been listening to this nonstop for the past few weeks lol.
Hajimete no Oto (初メテノ音) is basically a medley of popular/nostalgic Miku songs. I'm pretty sure you'll be able to recognize quite a lot of them. Some of my favs like Shiro no Kisetsu and Miracle Paint are in it :3 Some of the transitions are pretty funny XD
Niconico
Youtube
Part 1 Part 2 Part 3
Enjoy :3