How can i decorate my cage that's rabbit friendly?

i have a c&c cage that's a little more than 2 feet wide and 3 feet long, and has three floors. the flooring is mainly those peel and stick tiles you buy at the dollar store because my rabbit is not completely litter trained and i don't wan't him to pee all over the carpets. However, about 4 or 5 square feet of carpeting is available for him to lie down on throughout the whole cage. he's already decided that he'd rather sleep on the tiles and pee on the carpet :P but i'm getting him fixed soon anyways so hopefully he will become successfully litter trained soon and his cage can be almost all carpet :) And he has a large litter box filled with shavings on every floor. What could i put in the cage that's suitable for him, but that's also decorative. Like some kinds of toys or something :S thanks :)