Pinhole Cast On
The pinhole cast on (aka circular cast on) isn't extremely versatile, but it works well when you need to CO a few stitches in the round to create an enclosed end like for a toe-up sock, top-down hat, top-down mittens or amigurumi.
Pattern, Yarn, Needles and Notions
Thanks Ewe Ewe Yarns for providing yarn and to Skacel for providing the addi needles used in this tutorial. The needles are available locally at many yarn shops and online at Makers' Mercantile.