This is very simple and fun. Have the children hunt around the house for very tiny items to put inside their plastic ornament. We had letter tiles, marbles, hair ties, a piece of crayon, an acorn top, a dime, a tiny lego, a very small lego "head", a piece of a feather and more. Write each item on your tag that you will later attach so children know what to hunt for.
Place all tiny items inside your ornament. Then fill the ornament up with beads and shredded pieces of paper to make it challenging.
We recommend using hot glue or regular glue before you put the top on so your ornament does not spill later on. Be sure to write "I Spy" with a sharpie marker on it or sticker letters and also put the child's name and year on the bottom.