[JohanE]

We've built a lot on our own. Maybe Senchalabs Connect can help you, otherwise check https://github.com/joyent/node/wiki/modules. Don't know if it's better than devise/cancan though.

[Omni5cience]

Devise and Cancan are User Authentication middleware for Rails

Check out https://github.com/ciaranj/connect-auth I can't vouch for the effectiveness, but it seems to be under active development.