NodeChan is a decentralized peer-to-peer anonymous messageboard client. It has no central servers, and can never be censored, turned off, shut down, or otherwise interfered with.
Download the latest binary release - 0.8.0
Extract the contents of NodeChan.tar.gz, then run NodeChan from the command line by typing "java -jar NodeChan.jar [-options]"
NodeChan's source code and user manual can be found on GitHub.