What does your cat play with for fun?

When our girls were little it was not hard to find a toy for them. As they grew up, it is challenging to find "novelty" and make them interested. They get bored if you use the same toy every day, so we rotate different birds on strings attached to fishing rod.
The hot items for them are : scrunched foil balls, large scrunched sheets of wrapping paper and cardboard boxes.
One of our rooms is filled with multiple boxes and papers (playroom)
Every evening at 9:30 they meow to announce the playtime and invite us to participate. We take turns (both of us must participate, otherwise we'll hear more meows) They expect us to bring the fishing rods to the playroom. I have to be inventive and find different ways of play to keep them motivated.
At other times they do chasing, batting stalking each other or engage in self-play with foil balls.