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.
The Apache HTTP Server application 'httpd'.
The Apache HTTP Server is an open-source HTTP server for modern operating systems including UNIX, Microsoft Windows, Mac OS/X and Netware. The goal of this project is to provide a secure, efficient and extensible server that provides HTTP services observing the current HTTP standards. Apache has been the most popular web server on the Internet since April of 1996.
Xerces-C++ is a validating XML parser written in a portable subset of C++.
Xerces-C++ is a validating XML parser written in a portable subset of C++. Xerces-C++ makes it easy to give your application the ability to read and write XML data. A shared library is provided for parsing, generating, manipulating, and validating XML documents. Xerces-C++ is faithful to the XML 1.0 and 1.1 recommendations and many associated standards. The parser provides high performance, modularity, and scalability. Source code, samples and API documentation are provided with the parser. For portability, care has been taken to make minimal use of templates, no RTTI, and minimal use of #ifdefs.
Apache Axiom is an XML object model supporting deferred parsing.
Apache Axiom is a StAX-based, XML Infoset compliant object model which supports on-demand building of the object tree. It supports a novel "pull-through" model which allows one to turn off the tree building and directly access the underlying pull event stream. It also has built in support for XML Optimized Packaging (XOP) and MTOM, the combination of which allows XML to carry binary data efficiently and in a transparent manner. The combination of these is an easy to use API with a very high performant architecture!