I'm currently using em-websocket with Event Machine. It works great, but I also want to provide long polling and/or Flash fall-backs for browsers that don't support Web Sockets (and also so I can run it on Heroku).
I'm basically looking for a Ruby version of Socket.IO, or enough libraries to piece together to get the features I want. I've seen some examples that use Socket.IO, Redis, and a Ruby library that interacts with the Redis DB, but I'd rather keep it simple and just keep it all in Event Machine, rather than having to manage 3 applications instead of one.
Check out Faye - https://github.com/faye/faye.