Miitopia is a goofy RPG where all the characters are Miis—so you can go and do cute things with your pals / pets / creatures / popstars / etc. There's a demo in the eShop.
It takes a lot of Miis to fill out the cast! Fortunately you can easily grab Miis from Nintendo's collection of user-made ones. Unfortunately most of them are garbage. You'll need 45, plus the ones for your party.