I just think this is a great way to keep all those plant markers together for each season. Nice to have them to refer back to. Could actually use a label maker or write on the back side, how the plant did for you. For perennials, I actually keep these in my garden journal which is a 3 ring binder (stapled to a sheet of paper)
Make constellations in a tube. I actually do this a lot when we have a spare tube for my kids and for my former daycare I would take dark construction paper scraps and just put it around roughly flat and use a pin to push in the outline of whatever the kids wanted...Great reward. They love it. Or you can, as I did for the older kids, let them select the constellation and I would punch it in. Great cheap activity to WOW any child.