Exploring the German language
Asgard is actually a set of open source projects dedicated to exploring the German language in detail:
The most user-friendly subproject is Farbiges Deutsch, showing German rules as well as inferred statistical data in a colorful and effective way
Balmung is the basic library supporting the architecture, modeling the main German word categories
Odin is the core library of the project, providing a Hibernate-based repository for German lemmas, as well as a Wiktionary parser
Valkyrie is an experimental Scala application creating the data flowing into Farbiges Deutsch
I plan to use these tools to learn even more about German - and I hope you'll find them useful, too! ^__^!