The ASF is made up of over 100 top level projects that cover a wide range of technologies. Chances are if you are looking for a rewarding experience in Open Source, you are going to find it here.
LDAP and Kerberos, entirely in Java
The Apache Directory project provides directory solutions entirely written in Java. These include a directory server, which has been certified as LDAP v3 compliant by the Open Group (ApacheDS), and Eclipse-based directory tools (Apache Directory Studio).
Enterprise-class centralized version control for the masses
Subversion exists to be universally recognized and adopted as an open-source, centralized version control system characterized by its reliability as a safe haven for valuable data; the simplicity of its model and usage; and its ability to support the needs of a wide variety of users and projects, from individuals to large-scale enterprise operations.
Aggregated multi-channel documentation framework, separation of concerns.
Apache Forrest™ software is a publishing framework that transforms input from various sources into a unified presentation in one or more output formats. The modular and extensible plug-in architecture of Apache Forrest is based on Apache Cocoon and the relevant industry standards that separate presentation from content. Forrest can generate static documents, or be used as a dynamic server, or be deployed by its automated facility.