This is an annual cross-state ride called RAGBRAI. It's been going for 52 years now. Riders typically use support teams, but I ride self-supported from the center of the state, ride half the route, and ride home. More photos:
I have wanted to do RAGBRAI since I was in middle school. I'm 60 now and retired, so once I get my knees replaced, I think I'm gonna do it.