Logbot - irc services bot for logging, in perl
Net::IRCService is an interesting module - it allows you to make a “services” type irc bot, in perl, which can be much more hackable (in the good way) than most of the current irc services bots out there. I used it to make a bot that can be invited into channels to log their activity.
The main reason for a services bot, is it can speak server to server protocol - and therefore see new channel names as they are created. Based on this, this bot can join channels automatically based on regular expression.
http://gigo.com/ftp/pub/src/log-irc.tgz - BSD licensed.