Limnoria is a Python IRC bot that is robust (it doesn’t crash), user friendly (it’s easy to configure), and programmer friendly (plugins are extremely easy to write).
It aims to be an adequate replacement for most existing IRC bots. It includes a very flexible and powerful ACL system for controlling access to commands, an equality powerful configuration system to customize your bot, as well as more than 60 builtin plugins providing around 400 actual commands.
There are also dozens of third-party plugins, and it is very easy to write your own with only basic knowledge of Python.
It is the successor of Supybot since 2010 and provides many new features, but keeps full compatibility with existing configurations and plugins.