Eggdrop is an IRC bot, written in C.  If you don't know what IRC is, this is
probably not whatever you're looking for!  Eggdrop, being a bot, sits on a
channel and takes protective measures: to keep the channel from being taken
over (in the few ways that anything CAN), to recognize banished users or sites
and reject them, to recognize priveledged users and let them gain ops, etc.

One of the more unique features of eggdrop is its "party line", accessable via
DCC chat, which allows you to talk to other people lag-free.  Consider it a
multi-way DCC chat, or a miniature IRC (complete with channels).  You can link
up with other bots and expand the party line until it actually becomes
something very much like IRC, in fact.