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.
Annotator components and a scalable integration and deployment framework for Unstructured Information analysis
The Apache UIMA project supports the community working on the analysis of unstructured information with a unifying Java and C++ framework, tooling, and analysis components, guided by the OASIS UIMA standard. It includes support for very large scaleout using networked clusters of compute nodes.
Client-side HTTP implementation in Java.
Commons HttpClient is a library for client-side HTTP communication. It provides support for HTTP/1.1 and HTTP/1.0, plus various authentication schemes and cookie policies. Thanks to it's widespread use and years of development, it is a very mature and stable codebase. However, due to limitations in the API design, Commons HttpClient will eventually be replaced by HttpClient 4.0 with a completely redesigned API based on HttpCore.