Your Cat Will Be Endlessly Entertained by This DIY Cardboard Playhouse!

Using your string, cut a piece long enough to hang from the top of the door to about halfway down. Taking a small cat toy (I went with a toy mouse), glue one end of the string to the toy and the other end to the top of the door. Be sure to use a thick string that a cat won't easily chew through or swallow. Yarn and sewing string can be dangerous to cats, so avoid those.