I've worked up a sort of little howdah thing on the backs of the 3 dachshunds here. Each dachshund carries a number of CDs neatly stacked in the howdah. When the dog walks by, I pick out a CD at random, and replace it with the previous one. This has helped me listen to music I might otherwise have neglected, and it gives the dogs a useful function around here, which they most certainly did not have before.