Today, Andy Dawson (aka AD7six) announced in his blog that the source code of the cookbook application (which powers http://book.cakephp.org) is now available for everyone: http://thechaw.com/cakebook.
As you can see from the url, this project is hosted in a different place than other projects from the Cake team. It would be good if all such projects would be consolidated in one single place.
Anyway, here a list with places from where you can get the source code of those projects:
Update 2008-11-21: See also the official announcement of The Chaw.