Americans have grown much closer to their pets in the last 20 years or so, coming to regard them more as fellow family members rather than simply keeping them for some utilitarian function (such as rodent control). As part of this "warming" trend, cats now tend to be kept indoors to keep them safe from the risks of outdoor living.
An indoor-outdoor cat has hazards of traffic, dogs, other cats and wild animals with which to contend. If an outdoor cat is not killed or injured on the roads, shaken to death by a neighborhood dog, or injured by another cat or wild animal, there is still the risk of contracting some debilitating disease. Basically, it's not a safe existence out there and most owners now know that.
But indoor life can be tedious for some cats. They lack the all-important aspects of daily life in the wild, including the freedom to hunt, mark, protect and defend, and to interact with others of the same species.
It is our duty as cat owners to enrich our cats' indoor lives to make good some of these deficiencies. Without gainful employment cats merely exist within boring but luxurious homes. Also, without some species-specific entertainment, they may get into trouble, psychologically or physically, leading owners to seek behavioral modification advice… or not.
Below is a list of suggested means by which a cat's environment may be made more user friendly. The underlying principal is "think cat." If you do this you may even be able to add a few conceptions of your own.
The Big E's (Environmental and Managemental Enrichment)
1. Putting your cat's kibble inside a Buster Cube, a plastic cube with various compartments for food that falls out as the cat bats it.
2. Feeding kibble via a toilet roll tube, with the ends taped over and holes drilled in the sides to release kibble intermittently. (The tube rolls around and is fun to chase.)
3. Ping-pong balls with a hole drilled in the side to allow you to put a single piece of kibble inside.