## the routing...
r.match('/admin').to(:namespace => 'admin') do |a|
  a.resources :users
  a.resources :widgets
  a.resources :gadgets
  a.resource  :session

  a.match('/some_misc_thing_for_admins').to(:controller => 'something', :action => 'else')
end

## the results...
/admin/some_misc_things_for_admins results in Admin::Something#else being dispatched
/admin/users, /admin/widgets, admin/gadgets, admin/session, result in merb raising Merb::ControllerExceptions::BadRequest