I get newsletters from a few yarn companies, including Lion Brand and Patons, as well as from a couple of craft sites, including Crochet Me and Knitting Daily. In my knitting daily newsletter, there was a really interesting video about getting stripes to line up when knitting in the round, since that technique is really knitting in a spiral.
Anyway, Eunny Jang, the master knitter on Knitting Daily TV, demonstrated her stripe changing technique on a sock, and holy crap can that woman knit fast! She was knitting continental style, and did those needles ever fly. I knit maybe a quarter of that speed. So here's the video, though you don't see her knit until about 4 minutes in.
I wonder if there's a world record for the fastest knitter. According to this YouTube video and this one, it's Miriam Tegels from Holland. She managed to do 118 stitches per minute... which is almost 2 stitches per second. Wow. She also knits continental style, though the second fastest knitter in the world knits English style (a thrower instead of a picker).