Wow! Just when you thought you'd seen it all, here's a site devoted exclusively to SHOELACES! Ian's Shoelace Site "Bringing you the fun, fashion, and science of shoelaces". Science?!?
I've specifically linked to a page on the site about lacing shoes. Ian lets us know that "...mathematics tells us that there are more than 2 trillion methods of feeding a lace through the six pairs of eyelets on an average shoe...", but he fortunately only lists thirty-three.
Click the link and enjoy:
Shoelace Fun