Games like Dance Dance Revolution, Guitar Hero, Karaoke Revolution and Audiosurf aren't just music games, they're games that take existing music, and recontextualize it into gameplay, giving players a new way to experience music they might already be familiar with, or exposing them to new music with the tantalizing promise of a fun game. Without music, these games are just about timing a certain color or shape with a certain button press. They're playable with the sound off, but they're not nearly as compelling.

In the past year or so, some game developers have started toying with applying this same approach to text.