Covered Kitty Litter Boxes

You can buy covered kitty litter boxes at just about any pet store these days, and the litter boxes come in a wide selection of styles and shapes. Some have handles (how cool is that) making it easy to transport. They help keep odors from dissipating into the room, but they do intensify the smell inside the box.
Covered Kitty Litter Boxes:

Covered Kitty Litter Boxes example. Pictured: Clevercat Top Entry Litter Box