Apparently you guys demanded Dance Dance Revolution Universe 3, because it's now available on Xbox 360 Games on Demand.
Yes, for $29.99 you'll get a whole batch of new songs to stomp around to which you can expect to take up about 4 gigs of your 360's HDD. Of course, you'll have to have a dance mat, which means you may have to leave your house if you don't already own one. Which kind of defeats Games on Demands' purpose, which is to enable our lazy gamer habits.
You can add the game to your download queue online, or you can not do that at all. Your call.