The ASF is made up of nearly 150 top level projects which 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.
A 100% community-driven Bigdata management platform.
Bigtop is a project for the development of packaging and tests of the Apache Hadoop ecosystem. The primary goal of Bigtop is to build a community around the packaging and interoperability testing of Hadoop-related projects. This includes testing at various levels (packaging, platform, runtime, upgrade, etc...) developed by a community with a focus on the system as a whole, rather than individual projects. In short we strive to be for Hadoop what Debian is to Linux.
Server-side Tcl programming system combining ease of use and power
Apache Rivet is a system for creating dynamic web content via the Tcl programming language integrated with Apache Web Server. It is designed to be fast, powerful and extensible, consume few system resources, be easy to learn, and to provide the user with a platform that can also be used for other programming tasks outside the web (GUI's, system administration tasks, text processing, database manipulation, XML, and so on). In order to meet these goals Tcl programming language was chosen to combine with the Apache HTTP Server.