It is the simple things in life, right? Take a handful of marbles and a nesting of plastic mixing bowls (there was no way I was giving up my nice glass mixing bowls for this), give them to your children and watch what they do.
Are they looking at you like you lost your marbles (sorry, I could not resist). If that is the case then walk over, grab one of the marbles and give it a spin along the inner edge of one of the bowls. Then if you are lucky like me, you can walk away and busy yourself with making dinner or taking a long peaceful bubble bath because that is pretty much how long your kids will entertain themselves. At least if they are like my kids. I don’t know, maybe mine are just way too easily amused.
Marbles and mixing bowls. Just don’t expect to get your mixing bowls back any time soon.
If you want to get fancy and watch their eyes glaze over, you can bust out with your knowledge of centrifugal force and centripetal force. I did simply awful in both my semesters of college Physics so my knowledge of said forces is limited and probably mostly wrong (especially considering I passed because I hired a tutor, a friend who was an engineer that tutored for tequila, and the class was graded on the curve) but at least I sound smart when talking to my kids about it.