Toilet Paper Towers
Large package of toilet paper rolls (12 rolls or more work best)
Every time I purchase toilet paper, my sons love to open the package and build towers with the rolls. They try to build one as tall as themselves. They try to build two that are equal. It's a fun way to introduce math concepts like equal, same, more, and less. We also count the rolls in each tower. Of course they also love knocking them done and starting again.