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.
Support for Mono and Microsoft .NET development using Ant
This is a library of Ant tasks that help developing .NET software. It includes the "old" .NET tasks like a C# compiler task but also comes with support for NUnit testing or running the popular NAnt or MSBuild build tools.
Rule based XML->Java object mapping module
The Digester package lets you configure an XML->Java object mapping module which triggers certain actions called rules whenever a particular pattern of nested XML elements is recognized.
A feature-rich and extensible WikiWiki engine built around the standard J2EE components (Java, servlets, JSP).
Apache JSPWiki is a feature-rich and extensible WikiWiki engine built around the standard JEE components (Java, servlets, JSP). It features: - WikiMarkup/Structured Text - File attachments - Templates support - Data storage through 3 WikiPage Providers, with the capability to plug new ones - Security: Authorization and authentication fine grain control - Easy plugin interface - UTF-8 support - JSP-based - Easy-ish installation - Page locking to prevent editing conflicts - Support for Multiple Wikis