My friend Amy found them at Vineman this year, and sent me a pair. They are elastics held by little plastic thingies, and the plastic thingies in our case are... you guessed it... skulls! You choose the elastics based on size; they loop through they eyelets in your shoes and are held in place by the skulls. Amy originally sent me blue elastics with pink skulls, but the pink skulls didn't stand out very well on my pink shoes, so the fantastic people at RIP Laces sent me some white skulls instead.
They hold your shoes at just the right tension for running, and the best part is there are no laces to tie & untie when taking your shoes on and off! Actually, the best part is how fun and cool they are, but bonus in that they are also super functional. I've run with them quite a bit, and they stay snug and keep your foot secure in your shoe. Really comfortable too.
They have lots of different colours and styles... great for something like triathlon where speedy transitions are a must (and looking cool is a must), and also great for your regular around-town-kicks. I'm also thinking I could use the smallest elastics as hair elastics, and use my leftover skulls to hold them in place around a ponytail. Check them out at www.riplaces.com and let me know if you can think of any other uses too!