We are actively developing and working on Google Wave related projects, to see some of things that we have been developing why not check out some of the links on the site and if you have access to Wave play around with some of the robots and gadgets!
wave-vs.net use state-of-the-art Technologies, like Google Wave Protocol together with latest trends on Distributed Pair Programming Discipline to address Knowledge Sharing and Real-Time Collaboration challenge between Development Team Members.
everybodywave's project page. Below is a collection of Google Wave extensions (gadgets and robots) that I have developed, as well as other concepts that you may find to be useful.
Google Wave Federation Protocol technical discussion forum.
This forum is for discussing the federation protocol and the open source code hosted at http://code.google.com/p/wave-protocol/. For more information about the project and the community, please visit: http://www.waveprotocol.org/. As a best practice, you should always search the group, read the FAQ, and check the documentation to see if your question is already answered or is being currently discussed.
These projects make good starting points for your first contribution to the Wave code. If you'd like to take one on please post your intention to the development mailing list to check that no-one else is doing it and to find out the best people to support and guide your work. We're very friendly.