Mine likes his lava ledge. If you get one be careful to install it next to a cross member in the cage to prevent excessive bar flexing.
He also uses a hanging treat-k-bob with wood pieces of various shapes that is set up next to where he normally sleeps.
My chinchilla likes cardboard and will chew it in any form. If you do this make sure he does not eat large quantities (cardboard is filling but has no nutritional value) Cardboard pieces or tubes is a good outside of the cage toy. Printer paper is another thing he likes. He likes to play in boxes you get that hold soda cans. I recommend giving only cardboard from food packaging since it is printed with food safe inks.
