For litter boxes get this
http://www.litter-robot.com/
I have one and its amazing.... Kinda expensive at first, but over the life of a cat, its dirt cheap! I swap out the bottom tray one every 3 weeks, and thats it! Total life saver
If you have a spot next to some plumbing you can get this one, and not even have to empty the tray every 3 weeks.
http://www.catgenie.com/