In support of the march, the Pussyhat Project was started. Knitters, crocheters, and sewers are urged to make a pink hat with "pussy ears." You may have seen other hats with this design. Instead of decreasing in size from the brim to the crown, it's the same circumference all the way up. The top is seamed straight across so the two points form "ears" when you wear it.
There are several crochet patterns for this hat. Some are linked from the Pussyhat Project website. I found one on Ravelry that I really like. It's the Crochet Pussyhat by Gina Langridge. We only have 10 days left, but there's still time to make a hat and either donate it to a march or join a march yourself. Make 2 hats and find a friend to join you!