SimpleDB, yet another CMS
SimpleDB is a Simple Content-Management System, written in XSLT
All storage is done in simple xml files, which contain the db records and definitions about which tables should use which properties, and what kind of (html) widgets should be used to display it.
It is possible to create relations between tables, by use of xpath statements, xpaths can also be used to create functions to automize data-entry, for example a person has a name, which is a function that does: 'concat(firstname,' ',lastname)' and a date has an xpath as default value: date:date-time() (date module from exslt.org).
As the name suggests, this CMS is meant to be simple, and is not designed to be scalabe, so don't store more than 100/200 records in one xml file.