What about.. The week has 5 Days: Sliday, Cthulday, Quesday Zonday and Bunday (those are examples. Slimes, Cthulhu , Quest, Zombie, Bunny (i never miss them bunnies))
Terraria Community Forums
Kiroto
Nakano15
When I posted that, was because I were developing a mod for tApi, but I paused working on it because I am doing something else right now.