wow, lots of great ideas. thanks for the response, was definitely what I was looking for lol. I might have to try some of the ropes run across the mesh in my bins as well as the burrowing boxes.
I was also considering making a maze of some sort...try and see if I can breed smarter mice or something...lol! it'd be kind of neat to have a labyrinth for them to roam around and find snacks and what not.