Here are a couple of things that you can try. Feel free to share your fun ideas on my Facebook page (Lou Russell).
30 Circles: Print out this image. The idea is to fill in as many circles as possible with objects of some form or another with a pen or a marker. You have one minute to complete the exercise. For example, you can use one circle to put the first thing that comes to your mind, perhaps a smiley face.
Before you start, use the Customer empathy map above to identify what type of person your hat wearer will be, what their problem is and how you are going to solve it. In three minutes (set your phone), build your Tin Hat. Feel free to post these on my Facebook (Lou Russell) and win fabulous merchandise!