I once rode in a mountainous 220km event in central France, about 2000 starters, where each control stamp consisted of a number indicating the placing in the total field. So at the 1st control my stamp was something like 880, at the next it was 725, and so on. I thought that gave a great added dimension to the event, though, not being one of the world's natural climbers, it did half-kill me to keep getting lower numbers!