I did it 2 years ago. It was fun, except for the headwinds and oh yea, the torrential rain at mile 85. Oh, and watch out going up the road to Nubble Light. I got a flat that tore my tire. I did another ride there this summer and when I got home, my tire flatted. Very suspicious.
It's probably too late to sign up and I'm not prepared. I mean, I could probably do it and pay for it the next week. When is it?