BASKET DIVING! A great addition to your rat cage! :D
Give your rats boxes!!!
Why? They love them. Tissue boxes, big boxes, small boxes, box like things such as toilet paper rolls and cardboard egg cartons. They will have a ball. They will take them everywhere, they will rip them apart, they will play with them, they love them. So note: recycle your cardboard by putting it in your rat's cage!