Does anyone have any experience with cat exercise wheels? 

They have some videos on youtube and they look quite cool!  I was thinking of making my own because they are so pricey and won't let you return them if the cat won't use it...

Interesting idea!  All my cats could use a little more exercise to shed those extra pounds.  I'm afraid Rudi's huge swinging cat udder might tip it over though.  I'd need to have them make it with an extra wide track for him.

I've seen videos of cats using treadmills too.

Good idea these people have. Should they make the track wide a human could use it too to whittle down their mittle