The Twisted German cast on is very stretchy. It forms a tidy and sturdy edge, making it ideal for socks knit from the cuff down, mittens knit from the wrist up, and hats knit from the brim up.
Sande Francis made some excellent photographs of this cast on. You can find them here:
knitting.about.com/library/bltgcaston.htm
community.webshots.com/album/45031944ivzfxu (same photos, no popups)
