I just wanted to let you all know that I've found a toy which my cats love (well, two of them, anyway. The third one is a bit of a snob, no matter what).
It always frustrated me that my cats' balls would end up stuck under the sofa/fridge/oven after a few minutes, but this toy has put an end to that.
It's called The Cheese Chaser, and my cats spend hours playing with it! It's great!
If anyone knits, I made a pattern called Henry's Toy Snake. You can knit it up (the pattern is free), or you can commission me to knit one (or a few!) for you!