Oh yeah, I also made a hat.
This is based somewhat loosely on Wurm, a free pattern on Ravelry. I used the second half of my rainbow skein of Kauni Effectgarn. It's totally a trick, that yarn. It shifts colour very leisurely so that before you know it, you've gone through the whole rainbow spectrum.
The second half? Oops, I guess I must have forgotten to blog my Rainbow scarf/shawl. I finished it in early summer but now, I'm finding that it goes with just about every single thing I own.
The pattern for this one (not free) is written specially for the Kauni's long colour changes.
Back to the hat - I made some changes to make it better than the pattern. Specifically, I knitted the first row of each of the purl ridges as a knit row (to hide the transition better), and I hid decreases in the dark rounds so that my hat has a pleasant beehive shape rather than being long and kind of square at the end.
Unfortunately my skein of Kauni only had one bit that was truly purple so the colour transitions at the back of my hat (which are engineered; I have a lot of tiny skeins of the intermediate colours) are not as gentle as they could be. But I am pretty well satisfied with my new hat. It'll add a pop of colour when I wear my severe navy coat, once the weather turns really cold.