With moderately fine cotton and 5 needles.
Cast 2 stitches on each of 4 needles; increase 2 stitches on each needle; in the next round, increase 1 stitch on each needle; make a seam in the middle of each needle and increase on each side of it every other round, until you have a sufficient number of stitches for the size of your cap. Leave off seaming the middle stitches and knit round until your cap is 3/4 of a yard long, then finish the end like the beginning, decreasing where you before increased.
Here's what mine looks like so far.
Mine is knit with Brown Sheep Co. Cotton Fine (3 skeins) on size 2 needles (I started with 5 DPNs then switched to a circular needle. However, if you're doing this at an event, you'll want to keep it on DPNs). If you switch to a circular needle you'll want, at least, 4 stitch markers, these will be placed between the increase stitches and left in place till the end).You may want an additional 4 stitch markers to keep track of the "seam" stitch in the middle of each needle.
Gauge: 32 sts x 40 rows (4"x4")
Cast on 8 sts (divide onto 4 needles) join into circle being careful not to twist the stitches.
Set up row:
Knit into front and back of the first stitch on each needle (you should have 3 stitches on each needle now). The middle stitch will be the "seam" stitch (you will purl this stitch in every row).
Pattern Rows for Crown (increasing):
*Knit into the front and back of the first and last stitch, repeat from * for the other 3 needles. (remembering to purl the middle stitch on each needle).
Knit 1 round.
Repeat these two rounds until you have enough stitches to make the cap fit the recipient (you will want the cap to be 1-2 inches smaller than the recipients head. (On my cap it was 47 stitches per needle).
(Note: You can weave in the tail at the beginning after you've knitted a couple of inches.)
From here you will knit every stitch (if you switch to a circular needle you will need to knit the first 47 stitches, pm, knit 47, pm, continue until all stitches are on the circular needle) until your cap measures 27" long. You will then repeat the Pattern rows except decreasing where you increased, don't worry, it's supposed to look like a really long football. When you get back to the original 8 stitches, break yarn off (10" or so), weave in ends. Now, take the one end and tuck it inside the other (basically, your folding the cap in half). Congradulations, you now have a double layered hat!
It's not the fastest thing to knit. I'm about 2/3 done with mine (and running out of yarn - definitely need 3 skeins of Cotton Fine). , started it on December 8th and have 17" done on it as of this morning.
I hope that someone finds this useful. If you make this cap, I'd love to see it.