class User < ActiveRecord::Base; end
 
user.settings.notify_on.new_post = true
user.settings.notify_on.new_comment = false
user.settings.email_type = :html
 
class Event < ActiveRecord::Base; end
 
event.settings.has_comments = false
event.settings.show_map = true
 
...etc...
 
Was thinking of forking http://github.com/Squeegy/rails-settings and adding in a polymorphic owner to the settings table. Shouldn't be too hard to write, just hate reinventing the wheel.