Just saying, Tent is great. Good community, great third party developer support, and though for now it's just a Rails app you can run on your server, it's going to be something more abstract like IRC. The co-founders also really know their stuff.
I'm one of the Tent architects. Thanks for the kind words :)
Tent is actually a protocol, so anyone can implement their own server. We don't use Rails, but we do have reference server implementation called tentd that is written in Ruby: https://github.com/tent/tentd
