Royal blue baseball cap
The "A" depends on you, whether you like one of the comic book looks or the movie style. I chose a wider "A" simply because I was trying to cover up a design on my recycled cap.
And, that's all there is to it! Looking back, I might have first stiffened the felt or done something else to make it less frizzy as it wears. If I come up with a good idea, I'll add it.