I just heard about this interesting litter box called the Roll’n Clean from Omega Paw. It works the same way that the Litter-Robot does, but the Roll’n Clean is not automatic. You have to roll the box to the side until the top touches the ground (make sure no cats are inside!). This will run the litter through a screen, separating the clumps and depositing them into the built-in tray. Now roll the box back to the upward position and the clean litter returns to the bottom of the box. Simply remove the tray and dump the clumps. Easy!
The Roll’n Clean box comes highly recommend by Moderncat reader Olya from Toronto. Thanks, Olya! Available from Amazon and comes in two sizes, regular and large.