I got the treat ball at Pet People (the jingly ball too). I don’t know if it’s a national pet store chain or not but they’re one of the few stores that sells Oxbow hay and pellets – they also have a big emphasis on all natural dog and cat food
I’d just look for a cat treat dispenser – the dog treat dispensers are generally too big and heavy for bunnies, and the holes were too big for the pellets, and most of the dog ones were made out of rubber which i suspect would be very fun for sharp little bunny teeth to nip off and eat
Bren, I was worried Leroy would use his diggy box it as a litter box too, but he’s pretty good about his litter box habits, and honestly – he wasn’t impressed by the diggy box I made for him. Jeannie doesn’t use it either. :/ meh. You win some, you lose some
Elrohwen, that’s hilarious that Otto does that too! I think it’s the cutest thing ever when they get so wrapped up in their toys like that
And there’s all kinds of things you can do with a bunny that knows how to play ball… push it through a goal, drop it though a mini basketball hoop, put it in a “toy box” 
MirBear, I did some reading on catnip, and apparently humans can drink catnip tea, but it’s just calming for us, so idk if it will have the same effect on bunnies as it does on cats.