Instapaper has a feature called "Random Shake". Shake your device (iPhone or iPad), and it will call up a random article in your "Read Later" pile. Stuck hovering over 400 items in my list, I got it down by over 30 in a week. I'm happy with this as a way to decide for me what to read next.

Web Roulette! has a feature where you shake your phone to get a random website (within the list you've narrowed down to).