talkbox is a small and simple webchat built on node.js and jQuery. Currently, there isn't any spam filtering, also nobody claims it's secure.
But: It's super fast to deploy, has a minimal footprint and you might be able to learn something when looking at it.
It couldn't be simpler!
git clone http://github.com/cfstras/talkbox.js.git cd talkbox.js npm install npm start
talkbox.js is licensed under LGPLv3. See the LICENSE file for a copy.