I love the idea of reusing an item that would normally be thrown away. Here is a simple ornament that encompasses that very concept, making Frosty the Snowman's top hat from a laundry detergent cap. Parts of this project have to be done by an adult, but the fun decorating part is child friendly.
(1) Laundry cap
(1) can of Krylon Fusion spray paint for plastic OR Krylon Fusion primer
(1) package of hooks and eyes
Hot glue and Hot glue gun
Buttons, tree trimming items, beads, silk flowers, anything to decorate your hat.