As a cat owner, I'm all too well aware of the damage that cats can do to furniture. I'm not entirely sold on the idea of a treat-dispensing cat scratching post as the answer, however.
MAKE has the details on how to actually construct such a post. The basic idea is relatively clever, as the cat is attracted by a catnip cup at the top of the post. As he or she scratches the post, treats are dropped out of the treat dispensing section.
The thing is, I suspect one of my cats would work out all too fast how to break into the treat section if I pre-loaded it with treats, while the other one bit off the catnip cup and ran off with it. Either that, or I'd spend all day filling the thing, at which point cat obesity would once more rear its health-problem-inducing head. Maybe that's just my cats, but for now I'll be keeping to my standard strategy of a water spray bottle.
How-To: Cat Scratch Feeder [MAKE]