OH MY GOSH when I get a cat I HAVE to do this! It would be SO funny for a guest to go to use the bathroom, but the cat is using it! But like its still so awesome that the cat just uses the toilet. I wonder if you could train it to flush, too.
DIY top loading cat litter boxes plastic storage containers with lids feet of grey stair-tread carpet -carpet adhesive double stick tape. I like this idea, but i don't think my older cat would be able to jump out
Cat Whack a Mole - I feel like I could DIY this. Shallow wooden box (maybe even thick cardboard), drill holes, glue some sort of stiff durable fabric cut like that onto the holes, then glue a cat toy to a dowel!