I got this idea for Firecracker Crowns from Family Fun three years ago. My kids wear them every Fourth of July and always get a lot of compliments.
If your children are younger, you may want to cut out the foam strips ahead of time since that part can be time consuming. I recommend using foam star stickers instead of cutting and gluing the starts. I simply stuck two stickers with the sticky side together at the end of the pipe cleaners.
If you live in a humid area, use duct tape instead of masking tape. The first year we wore the hats, the tape fell off from the humidity when we walked outside. We were able to repair the hats using duct tape and haven't had a problem since.