If you tear up tissue into smallish pieces and put them into your hamster cage, they’ll chew them up and line their nests with them. One of mine gets pretty fancy about it, too. This always makes me feel guilty when I clean the cage, because it destroys her fancy nest-work and has to start all over. I guess it gives them something to do tho.
The lighter grey hamster has learned that a hand inside the cage equals probable tasty treats, and thus she stands up on her hind legs, waving her front paws in the air to grab my finger in anticipation. Sometimes she even stands up like that if she sees I’m walking around in the room. She kind of looks like a mini-dancing bear. I could probably train her to walk on her hind legs as a ‘trick’, but I’m too lazy. It’s really cute tho.