Some more ideas.
If you've got an empty celebrations or similar tub left over from Christmas you can use it to make a hidey toy:
You need to mark out circles with a pen and then cut them out with a hot Stanley knife - then file down with sandpaper or a nail file so there are no sharp edges. You can also put a hole in the tub itself to get in and out. Nevy loves going in and out of the various holes and running round inside scent marking all round the sides. You can also use it up-side-down without the lid to make an igloo style nesting box. I was going to plasticote this one but never got round to it.