You can join the #disc0rd channel on the Liao IRC network either through the web client in your browser (easiest), or with a traditional client.
If you want to use a non-web IRC client (HexChat is good), join #disc0rd on irc.liao.ws (traditional connection string: irc.liao.ws +6697).
That's all that's required.
There used to be a Discord, but Discord is gay and I hate being one of those sites that shouts about its Discord circlejerk instead of focusing on the site itself.