I finally managed to find the right colours to make R2D2 hats. I've been thinking about making these since the summer! I just spotted the yarn (Vanna's Choice) when I was at Michaels getting a gift card for my sister-in-law.
These hats are for my nephews, who are 2 and 5 years old and just love Star Wars!
(ETA: action shots in this post: http://www.craftster.org/forum/index.php?topic=367979.msg4327882#msg4327882
I made up the pattern as I went on the first hat, working from the bottom up. Then I made a second hat, intending it to be just slightly bigger than the first (which seemed very small to me) and it ended up being HUGE. Too big even for me to wear! So I made a third hat, the same number of stitches per round as the first, but with an extra round of grey in the middle to make it a smidge longer.
The general directions for the hat, working from the top (as I did with the last hat), are:
6mm hook, Vanna's Choice yarn
All following rounds are "work 1dc in each dc" until you've reached the desired length. I ended up with 13 and 14 rounds on the hats.
Then it's just a question of plugging the colours in where needed. I did the first two rounds in blue, the next in grey, the next was mostly blue, but with 6 evenly spaced grey stitches, the next is the same (put the increases in the blue sections), then 4 or 5 rounds of just grey. Do smallish blue blocks on the next two rounds, making most of them 2 rounds tall, but a couple at the front only one row tall, then a round of grey, a round of blue, then a round of grey.
With black, do 12dc into a ring. Then around the outside of that, do *5dc in next stitch, hdc in next 2 stitches* four times in blue. Leave a long tail and use it to sew this onto the front of the hat.
These are smallish hats, that will (hopefully) fit small kids. To make it adult sized, add stitches to R6. I added an extra 6 there and it turned out too big.
Of course, it all depends on the yarn you use.