Is there any CakePHP ACL-like plugin for Rails?
Although I'm not directly familiar with CakePHP's ACL functionality, you might want to check out CanCan by Ryan Bates:
CanCan is an authorization library for Ruby on Rails which restricts what resources a given user is allowed to access. All permissions are defined in a single location (the Ability class) and not duplicated across controllers, views, and database queries.