We have just returned a police car we got from the toy library. Michael and Marcus take turns climbing inside and pushing themselves up and down the hall. I have also seen Marcus pushing Michael around in it quite gently, which was sweet.
I was in a very lazy parenting mood last night so I subdued a minor ruckus by putting on a video. Michael cruised to a position where he could see the TV, then sat back in his vehicle quite comfortably, with his foot on the dashboard, to watch Little Robots. He just needed a takeaway coffee and bag of doughnuts.