There are a few examples around the ‘net of chat servers in Ruby, which seem to me to be unnecessarily complex or else too simplistic.

This is a simple version, too, as it is intended to meet the requirements over at RosettaCode. However, I think I’ve covered most of the common failure points.

Caution

If connecting with a client like PuTTY, use “raw” mode to avoid telnet negotiation.