I have downloaded a game app called Beat Beat Vocaloid. It is a free to play app for the Android OS. Fans of the vocaloid created songs can play this game and listen to the song at the same time. It is a rhythm game. Warning: It can be hard to start at first. It requires you to have quick reaction time to even play at the easy mode. It can be challenging. The only draw back is that it tends to have "failed download" errors at times. This requires patience for you to wait. Good think it is also available for play offline.