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.
See the issue list. Bugs that are easy to get started on are labelled "StarterProject".
The client needs to generate random tokens for new wave ids, etc. To ensure domain-wide uniqueness the server should pass a unique seed to each client.
Our ant scripts are not well suited to rapid development. There are no good targets for rapid build/test cycles. For example, rather than require the "dist" target to build servers for testing, testing servers should run from the compiled class files (in progress, contact anorth to help out)
No-one is working on mobile support at the moment. This is an open project.
While other aspects of the Robot API are being flushed out the interface for implementing operations has been committed. This allows a heap of operations to be implemented, ranging in difficulty from easy to tricky. The list of operations that we'd like to have implemented are shown here.