Awesome

CIRC

An IRC client in the shape of a packaged Chrome app

CIRC uses the chrome.sockets APIs to connect directly to IRC servers without needing a proxy. It has a ton of other killer features as well such as syncing your IRC state accross all your devices and allowing you to use a single IRC connection on multiple devices simultaneously.

Get it on the Chrome Web Store

Check out the documentation: https://github.com/flackr/circ/wiki

Join the official channel at #CIRC on irc.freenode.net.