We used to have a litter box set up in the spare bathroom but as neither Au nor Target used it, we eventually took it away.
When Guido joined our family, we put up a litter box for him. I thought it would be temporary because cats tend to prefer the fern patch we've set aside for them in the garden.
Guido did prefer the ferns but Au decided that his old bones need an indoor loo.
Unfortunately our senior cat was too big for the standard cat tray and when I looked at the prices of a commercial cat loo, I almost died of a heart attack. I mean, RM100+++ for a piece of plastic???

I wanted something large so Au could turn around comfortably, and something with tall walls so he could kick the sand about without making a mess. When I went out I discovered that baby baths are ideal.
Here is ours - complete with Au as feline model.
The baby bath cost RM19 and it is filled with three types of sand. There's the clumping stuff so it's easy to clean, the white soft stuff that Au loves best, and a sprinkling of odour absorbing stuff just for being fancy.
As it's a big, deep loo, it has tonnes of sand, which also means its' easy to clean. I clean twice a day by scooping and I replace all the sand about once every 3 weeks.
Every time Au uses it, I can see him think, "This is pawsome!"

PS we've got 2 new books out, and we're giving 25% off as an Early Bird deal. Price until July 30th 2012 is now $1.49.
Check out previews and downloads here:
Katz Tales The Adventures Of Scoop and Au
Katz Tales Au And Target The Early Years