So, how do you keep a cat who lives indoors happy? Most say that if your cat hasn't ever been outside, he should be just fine staying inside. Making an outdoor cat stay indoors can be a little trickier, but with some resolve on your part, it can be done.
The first order of business is to refuse to let her out, despite the verbal abuse you're probably getting. You can at least allow cats access to your screened porch, if you have one. If not, and you're willing to invest a little to help your cat acclimate to indoor living, you may want to consider a cat enclosure. This is a small structure that lives outside and connects to your house through a kitty door that allows your cat to spend time outside in a contained environment. You can buy a prefab enclosure or make your own out of chicken wire or nylon mesh; just try to make sure it's a material that your cat can't rip open.
You can also try to leash train your cats and take them on walks. This is easier to start when they're young, but it's worth a shot if they're really complaining about being stuck inside. If outdoor time really isn't an option, then make sure they have access to sunny windows. Giving them a perch near a window will make them very happy.
Kitty condos, which are multi-level, carpeted "trees" that cats can climb and lounge on provide hours of enjoyment. And don't forget a scratching post to keep them from doing it on your furniture. If they don't have a buddy to play with, then you should schedule in a little playtime to toss around their toys and let them run. And always keep a stash of catnip around.
Last but not least, keep their litter box clean. It's a grim job, but cats like a clean house, and they're bound to let you know if you're not doing a good job.