Who doesn't like a wacky hat? (If you dare to actually wear it...)
There are lots of possibilities for this... I have no idea how to knit or crochet, but I can sew and do paper mache, both of which are used in hat-making. Or take something and turn it into a hat. For an after-school project once, I had the kids make a hat out of a small paint bucket and it had an electrical outlet on the front of it. Truly wacky!