I've had the left over yarn from my bear knitting project just sitting in my yarn basket for ever. The other day when I stupidly left my best winter hat in a friend's car, I decided I needed to knit myself a good back-up hat. My co-worker told me about the Mandlebrot pattern from Knitty and I quickly cast-on that evening.
This is a pattern that can definitely be done in one day, but it took me two because I had to redo the crown. I used size 10 needles for the band of the hat and initially used size 9 dpns for the crown. (I didn't even bother with using circulars, as suggested in the pattern, as I could fit everything on dpns.) Using 9s prooved to create a teeny tiny crown, so I ripped back and redid it with size 13s. Way better fit and slouch, thankfully. I couldn't resist putting a comically large pom pom on top of the whole thing because who does't need a little smile in winter?