Awhile back I bought a pack of these plastic baby rings for the bunnies:
Similar to these.
I hung some from the top of their NIC cage so they would dangle and some I hooked together to make a tossing toy. Neither bunny was particularly interested in them. I’ve kept them around just in case the bunnies changed their minds.
A couple days ago, I hooked some to the Nibbles’ gate. Well, he loves it! He’s been tugging at them, digging at them with his paws, and generally looks like he’s having a grand time trying to get it off the gate. Sometimes it takes him just a minute, other times he pulling at them for 10+ minutes before it comes off! I think he’s enjoying it…you watch and see what you think. He either loves it or he’s really annoyed that I keep putting these things on his gate!