I haven't ridden a lot of centuries, but the ones I've done weren't in any way organized as races. Sure, there were groups of riders competing with each other, and lots of riders working on improving their "personal best," but there were also many many riders just out there to enjoy the camaraderie and the scenery, not to mention having a nice, long ride with someone else setting up the route for you and laying on the bananas and gatorade every 20 miles or so.

But I was under the impression that actual bicycle races are a lot more formally organized than that, with categories of racers and prizes and sponsors and all that.

Any racers out there with any clarify info on this topic?