The ASF @ 15 - The Apache Software Foundation Celebrates 15 Years of Open Source Innovation and Community Leadership http://s.apache.org/wZr
... and cheered at ApacheCon Europe http://s.apache.org/1o4
The ASF is made up of more than 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.
Apache DataFu is a collection of libraries for working with large-scale data in Hadoop. The project was inspired by the need for stable, well-tested libraries for data mining and statistics.
Apache DataFu consists of two libraries: Apache DataFu Pig is a collection of useful user-defined functions for data analysis in Apache Pig. Apache DataFu Hourglass is a library for incrementally processing data using Apache Hadoop MapReduce. This library was inspired by the prevelance of sliding window computations over daily tracking data. Computations such as these typically happen at regular intervals (e.g. daily, weekly), and therefore the sliding nature of the computations means that much of the work is unnecessarily repeated. DataFu's Hourglass was created to make these computations more efficient, yielding sometimes 50-95% reductions in computational resources.
Web development framework: separation of concerns, component-based.
Apache Cocoon is a web development framework built around the concepts of separation of concerns (making sure people can interact and collaborate on a project, without stepping on each other toes) and component-based web development. Cocoon implements these concepts around the notion of "component pipelines", each component on the pipeline specializing on a particular operation. This makes it possible to use a "building block" approach for web solutions, hooking together components into pipelines without any required programming.
Simple encoders and decoders
The codec package contains simple encoder and decoders for various formats such as Base64 and Hexadecimal. In addition to these widely used encoders and decoders, the codec package also maintains a collection of phonetic encoding utilities.