I haven't been on subeta much recently, and I noticed that a new category in the achievements revolves around this atebus revolution masquerade thing... Can someone briefly catch me up on what this is about, or tell me where can find info on this? And are the achievements ("ask a user to dance", etc) still do=able? Thanks!

The Achievements are no longer available. As for what it was about, read this Subetapedia article.