So Doublefine, the makers of games such as Psychonauts and Brutal Legend have an iOS game on the way. It's called Dropchord. All we know about it is that it's a rhythm game, and a teaser trailer was just released. And here it is!
The trailer just confuses me further honestly, but Doublefine do have a good track record for unique games so we'll have to wait and see when more information is released.