I just made my cat a new toy with an empty tissue box and a ping pong ball inside. He went nuts trying to paw out the ball; and when he finally got it he dashed across the room with it. Give it a go!
I've been doing that for two years now. I like to stuff SEVERAL toys in there along with some treats - it gives them fun stimulation because they have to work to get the toys and treats out.
Funny thing is, now when I have a box that actually has tissues in it, I find the cats trying to stick their heads in to see what's under the tissues!
We tried it with one of the smaller square kleenex boxes once - and Flowerbelle shoved her head into it, and we almost died laughing watching her try to shake it off! (We only let her suffer with that thing on her head for about 30 seconds). But the kleenex box game is a great one!