This aspect of feline behaviour is simple to understand once you realise that a large part of cat philosophy is based around the statement "anything you stole is better than anything that was given to you".
This is why even if you give the cat the finest breast meat from the roast chicken while you and your family make do with the stringy wings and legs, the cat will still leap onto the table and run off with your share if you turn your back on the plate for even a tenth of a second.
Kong Kickeroos - I highly recommend them.
Kong first made dog toys - and when they started a line of cat toys I had to try them. They're really well made.... My dog had toys from Kong that lasted her entire 15 years.
I bet your cats like to hold these with their front paws and claw the heck out of them with their hind claws right? Yup that's what the big Kong toys are designed for.