My daughter had an I Spy bag that my sister made for her, but it had a small hole in it. The filling was slowly leaking out. Since we had some clear plastic ornaments that we hadn't filled yet, we decided to try making some I Spy Christmas ornaments and my daughter was very happy with how they turned out.
This would be a great gift for kids to make and they could really get creative with personalizing them for the recipient. All you need are clear plastic ornaments (I bought mine from Walmart), small clear beads (ours is actually the filling used to make dolls), and anything small enough to fit through the top of the ornament. Ours has buttons, sequins, Barbie shoes, Legos, letter beads that spell out their names, dice, a small cookie cutter, coins, charms, and lots more.