I'm making another one now. This one is a tad small, but I ran out of yarn. I decided to use red to finish it off, and I think it looks kind of neat. It's a feature, not a bug!
This hat is created from entrelac squares that are done in ribbing. I used 3 by 3 ribbing because it's quite stretchy and I didn't want to swatch or anything. I figured with the stretchiness the hat would fit my head no matter what.
I'm writing up a pattern for it. More pictures of this on my Flickr account, and more info at my Ravelry page (user name "yarnover").