Minimalist IKEA Cabinet Hack, and lots of other ideas on hiding a litter box. Not just for the litter box but for a dog's or cat's pet bed, when company is over or just during the day, just shut the door and it won't have to be seen until bedtime.
Even in a tiny house - there's room for something like this - DIY Children Stove with Oven – Ikea Hack. Link is in a foreign language, but the picture shows it well. Cheap end table turned into toy stove. I would have loved this as a kid!