My husband decided to teach my kids a new trick this evening. He lay down on his back on the floor, cupped his hands behind his knees, and alternately bent and straightened his legs in rapid succession, thus creating a noisy squeak. The kids thought that was great. Of course they had to learn how to do it.
After about five minutes, all of my "kids" were on the floor in my son's bedroom squeaking their knees. What a sight! I just stood there shaking my head.
(I think I know what my kids will be doing tomorrow. Thanks, Daddy!)