I must be a sadist. It's the only answer that makes sense.
Our driveway is paved, in the looser sense of the word. There's a sheet of concrete/gravel, and then lots of gravel on top of that. So if you have a kitten rolling around on the driveway, and you pet them, there would also, hypothetically speaking, be lots of small gravel close to hand. Theoretically, you could pick up the gravel and drop it, one piece at a time, on or next to aforesaid kitten and watch him jump and turn and pounce and turn himself inside out to catch the invisible piece of noise. Even better-ahem, still theoretically- all the gravel looks like all the other gravel so the kitten doesn't know what he's pouncing towards.
Not that I would ever do this while I wait for the Teacher to come out of the house and drive me somewhere.