CancelBot is collection of modular scripts for the XChat IRC client. I started CancelBot, which is now a GPL project hosted on Sourceforge.net late 2004. I wanted to provide XChat users, especially those coming from other platforms with the same kinds of scripts they were used to on their previous platform and then some. CancelBot was originally written in Perl. At the time XChat didn't support individual loading and unloading of scripts so I decided to rewrite everything in Python. I really fell in love with Python during that process.
The module I'm most pleased about in the project has to be TransBot. TransBot can auto-translate to and from different languages. You can be in a chat room and basically say translate anything John says from Japanese to English and translate everything Jane says from English to Spanish. It's really nice to hear back from users every now and then about how it helps them communicate every day.