Nomad PIM is a free extensible personal information manager. It contains modules for personal notes, journal, address book, personal finances, task management, time tracking and evaluating basic fitness measurements.
The Eclipse XML Meta-Modeling Tools project provides tools like editors, extended validation and generators for developing xml based meta-models and domain-specific languages in eclipse.
The Eclipse XML-Security Plug-In allows you to experiment with the W3C recommendations on digital signatures and encryption and to learn all about their background. Arbitrary XML documents can be canonicalized, signed, verified and en- or decrypted.