I know that this forum has an audience that tends to be a bit more mobile than most others, and more likely to be able to be in the area for this event.
A Simple Century
It's an open, unsupported event, organized loosely my the South Florida Bike Club who hosts similar meetup events around the So Fla area. The ride is and "out and back" and will basically go up A1A 1/2 way, turn around, and return to the start. Hence you can do any distance you wish.
If you are in the area, you are welcome to join.