This one looks fairly easy:
thanks I got three cats I try to play with them as much as i can this one looks fairly easy just like you said im thinking about putting a easy cat toy project on instructabels i made it for my cats and they love it oh and if you have some money you can buy a laser for your cat make sure the laser is not that powerful i bought mine shaped like a mouse because it is made for cats mine only shines about 50 yards at night but any laser with low power will work
Find some strong cardboard boxes the right size and attach them together in a nice arrangement. Cut holes in the sides and between them for the cats to prowl thru. Cut some squares of cardboard to fit inside and glue some on the outside for climbing.
Our kitten real likes the box we brought her home from the Humane Society in- we just put it up on a kitchen chair, on it's side so the flap hangs down. She likes to ambuse the dog from this perch.
If your looking for a quick and easy solution you can take a cardboard box and cut holes in the side and top. You can use cardboard untill you find a design that you and your cat like. From there you can take your cardboard and trace it onto OCB board, cut it out, and staple old carpet to both sides. To add more you can attach pipe cleaners and strips of cloth for your cat to play with. Hope this helps, Eric