Anybody drink juice made from concentrate at your house? We certainly go through a lot of orange juice around here, and I always buy the concentrate that comes in little cardboard tubes with metal ends. I've realized that there are plenty of ways to make use of those little metal juice lids if you're of a mind to save them. I just wash and dry them and save them in an old formula can. One of the things I've done with my lids is make a memory game for my girls to play.
My kids also use the lids as pretend coins for when they're playing "grocery shopping." Sometimes they will make a tall stack of them and see how high they can get before it falls over. They lids are fun to put in the formula can and shake around because they make a nice jingling noise.
I've also seen people use these to make Christmas tree ornaments. You just take a nail and hammer and punch little dents in the lid to make a picture of a tree or star. Then punch one hole all the way through and tie a ribbon through it to hang the ornament on the tree.
Anyway, I'm sure you can come up with many more ways to use these little lids, and they are essentially free if you'd be buying the juice anyway. It's a cheap way to have fun with the kids. Try it!