Sometimes they hang out on the top and look out the window or catch a quick nap.
Sometimes they hang out on one of the 2 lower levels and play with the dangling mousies. This is probably Bert's favorite activity.
If you have kitties I'm sure they'd love to have their own Jungle Gym. I got the original one at Target but couldn't find it on their web site. Last time I was looking in the pet area I did see one similar to this so hopefully if you want one you can find something close cause - my boys really love it!