Our club just had its annual century. We had 80 volunteers. That included route marking, manning the rest stops and post-ride picnic, on-site registration and sign-in, directing cars in the parking lot before the ride, driving SAG vehicles, etc. A small group of people put a huge amount of time into managing it, including determining the route, writing and printing cue sheets, managing pre-registration, advertising, buying food and beverages, coordinating with the people at the rest stop locations and ride start/finish, coordinating volunteers, getting permits, etc.