Peribot is no longer in active development. Its components are kept on GitHub in the hope that they may be useful to others, but please keep in mind that they have not been maintained for some time, and may fail to operate as originally intended.
Why? Peribot was developed as a basis for some GroupMe chatbots that I personally operated. Those bots are rarely used anymore, and Peribot is not used elsewhere to my knowledge. Thus, I no longer have much reason to invest in this project.
Thank you for your interest, and sorry for the bad news. The Peribot README continues below, but please note that parts of it may become outdated over time.
Peribot is a message processing framework in Ruby, designed mainly to facilitate the creation of IRC-style bots for services like GroupMe. That is, it is explicitly designed to provide a common set of services for multiple "groups" at once (in contrast with frameworks like Hubot that generally operate with a single set of users).
The framework is designed for responsiveness and ease of development. The concurrent processing model ensures that individual groups' actions don't lead to delays for others, while facilities provided by the framework make it easy to develop powerful, thread-safe services. Configuration is designed to be simple and fast for bot maintainers.
With Peribot::GroupMe, running a GroupMe bot is as simple as running a Ruby script. Thanks to push notification support, there's no need to run a web server and manage callback URLs.
Framework classes are pretty well-documented, and may be a good start toward understanding Peribot. I have also made several resources available on the Peribot wiki, including the Zero to Peribot tutorial (which is designed to help you set up a basic bot with Peribot).
Peribot is available under the terms of the MIT License.