As promised, here is a hat from the pattern I recommended yesterday, in pictures:
On the left, the finished hat. On the right, with the brim folded up. Unstretched, the circumference is 7.5 inches (19 cm); it stretches to 15 inches (38 cm). I cast this on yesterday using some no-longer-labeled 6-ply sock yarn I had lying around; the hat took well under 50 grams. I wonder what else I can find. . .