CruiseControl.NET has been registered on OLOH, a repository of statistics and information on different popular open source projects. If you are using CCNet and you feel so inclined, please check out the site and give CCNet a review or a rating and stack it.
According to the collected statistics, we've expended an estimated 22 person years on this project (based primarily on code changes), which at a (low) salary of $55000USD puts the cost of replacing the project at a cool $1.2M. *sigh*