One of my favorite cast-on methods for starting a knit project from the center. (Crocheters might notice that this is very similar to the magic ring) Pinhole Cast On for Circular Knitting Movie (right handed)
Emily Ocker's Circular Cast-On This technique comes from Elizabeth Zimmermann's Knitter's Almanac (Dover, 1981). Make a simple loop of yarn with the short end hanging down (Figure 1). With a crochet hook, *draw a loop through main loop, then draw another loop through this loop (Figure 2). Repeat from * for each stitch to be cast on (Figure 3). After several inches have been worked, pull on the short end (shown by arrow) to tighten the loop and close the circle.