Erwin
Erwin is an IRC-bot in Perl, using POE.
..., searches Google with that keyword and returns a couple of URLs.
Further expandability can be achieved using "plug-ins". Plug-ins subclass "Erwin::Plugin", and can recieve and take control over various events. For example does the pastebin-plugin need the ability to take control over every line sent privately by some user, and e.g. a quiz module would need to get every single message sent to a channel while a quiz is going on.