Shirk is a modular IRC bot based on the Twisted framework. It is designed to be easy to write modules for so you can focus on the things you actually want to do. After all, if you wanted to mess with IRC internals you wouldn't be using someone else's bot.
I needed an IRC bot for a certain project. Didn't feel like using one of the existing ones as they were either out of development or too much of a hassle to write plugins for. Instead, like the curious fool I am, I decided to look into writing my own. The project died, I got bored, the project was restarted and here I am starting all over.