Bluehorn Reader crawls RSS feeds and makes their content available to clients (only a browser client exists currently). It supports multiple users, whose sessions' look and feel can be customized based on each place they log in from. A potentially useful feature is that, while it should be able to support a large number of users from a single host, if that is not enough, more hosts can be added to share the load, with only minor configuration tweaks. The Web server part is mainly in JSP, so it should be easy to play with it and adapt it to support other use cases.
OOS is a C++ object-relational mapping (ORM) framework. It aims to encapsulate all of the database backend functionality and keep it away from the user. One don't have to deal with database backends or SQL statements, nor with mapping of data types or serialization of objects. It provides an STL-like API and one container for all persistent objects - the object store.