I "designed" that cap in about 15 minutes. I went to my craft room, grabbed a skein of Bernat Softee Chunky and a size 15 circular needle and did a garter stitch swatch. Then, I measured around my head and figured out how many stitches I would need to cast on to fit it tightly.
(I stretched out the gauge swatch to see how many stitches would stretch out per inch. The resting gauge was 11 stitches per 4 inches, and the stretched gauge was 6 stitches per 4 inches.)
Figuring that I would need to cast on 36 stitches, I got to work. After knitting for 6 inches, I did a normal decrease like other hats I've made, then ran the yarn through the stitches when I had about 8 or 10 stitches left on the needles.
I think it only took about an hour to make it. Next, I remembered that I had the flower pin with my sewing stuff, so I pinned it on the hat for the final touch.
Then, I grabbed my hubby, and said, "Come and take my picture wearing this silly hat."