I knit this cap as part of my halloween costume this year, but boy does it feel good of a night in this draughty old house! I'd wondered for years how those things were made; you see them sometimes in 15/16th century portraits.
I think I got my inspiration on here for it, but now I can't trace the pic/ post that gave me the pattern. It's an ingenious scandinavian design (called djeveluer--devil's peak) worthy of Elizabeth Zimmerman! Basically, its a zig-zag piece of garter stitch knitting (the number of stitches in each row remain constant, but they are constantly slanted to create an exaggerated "VVV" shape of flat knitting. Then you join the four points at the back of the head where you 'turned the corner' of the VVV, graft the edges together, and voilà, an instantly shaped hat that fits snugly to your head and 'gives' in exactly the right places without riding up on your head and falling off (my main annoyance with watchcaps/tube caps).