I believe that ATB always sells out right around the time that the price jumps. I am trying to remember - they didn't always have a cap, did they? Wasn't it after the year that the people finishing near the end only got stale chiabbata buns for the post race food (or got nothing) that they put a cap on the numbers attending? I know that we were some of those people who arrived at the finish line to find next to nothing to eat. This was their way of trying to ensure that this didn't happen again. Truthfully, I think that putting a cap on a race makes it more exciting, and somehow makes more people want to participate. I guess it is a marketing ploy that works -- as long as you have a good quality race that is! I do not like races that take your mailing address at the finish line because they ran out of medals because they let an extra 1000 people register the day before the event!

Neil if you read Runningmania.com they have tons of discussions on races, what is getting close to selling out, etc. It is a good way of monitoring what is happening in that department. They also have reviews of many, many races.
Anyhow, I hope to be out running on Sunday. I will probably do one loop again -- or if people are going a bit farther, I may go a bit farther too.
