During Nintendo Direct, Nintendo announced a rhythm platformer for the 3DS eShop developed by the folks over at Gamefreak (known for developing the Pokemon games).
An Iwata Asks interview gives more insight on the game. The rhythm-platformer was the idea of Gamefreak employee James Turner (UK). Pokemon game director Masuda directed the game and commented on the difficulty of starting projects not involving Pokemon due to the heavy focus on Pokemon within the company. It was also said that the game started off as a side-scrolling DS game at first.