diff --git a/app/models/asset.rb b/app/models/asset.rb
index 69322400..fe4c3041 100644
--- a/app/models/asset.rb
+++ b/app/models/asset.rb
@@ -24,5 +24,5 @@ class Asset
       self.content_type == type
     end  
   end
-  
+    
 end
\ No newline at end of file
diff --git a/app/models/asset_collection.rb b/app/models/asset_collection.rb
index 9150f32b..80b6dae5 100644
--- a/app/models/asset_collection.rb
+++ b/app/models/asset_collection.rb
@@ -5,11 +5,14 @@ class AssetCollection
   ## fields ##
   field :name, :type => String
   field :slug, :type => String
+  field :asset_fields_counter, :type => Integer, :default => 0 # FIXME (custom fields)
+  
   
   ## associations ##
   belongs_to_related :site
-  embeds_many :assets
-  # has_many_related :assets
+  embeds_many :assets, :custom_fields => true
+  
+  embeds_many :asset_fields # FIXME (custom fields)
   
   ## callbacks ##
   before_validate :normalize_slug
diff --git a/app/models/asset_field.rb b/app/models/asset_field.rb
new file mode 100644
index 00000000..b04c3f9c
--- /dev/null
+++ b/app/models/asset_field.rb
@@ -0,0 +1,67 @@
+class AssetField
+  include Mongoid::Document
+  include Mongoid::Timestamps
+  
+  ## fields ##
+  field :label, :type => String
+  field :_alias, :type => String # need it for instance in: > asset.description (description being a custom field)
+  field :_name, :type => String
+  field :kind, :type => String
+  field :position, :type => Integer, :default => 0
+    
+  ## associations ##
+  embedded_in :collection, :class_name => 'AssetCollection', :inverse_of => :asset_fields
+  
+  ## callbacks ##
+  before_save :set_alias
+  # before_create :add_to_list_bottom => FIXME _index does the trick actually
+  # before_save :set_unique_name!
+  
+  ## validations ##
+  validates_presence_of :label, :kind
+  
+  ## methods ##
+  
+  def field_type
+    case self.kind
+      when 'String', 'Text', 'Email' then String
+      else
+        self.kind.constantize
+    end
+  end
+  
+  def apply(object, association_name)
+    puts "applying...#{self._name} / #{self._alias}"
+    object.class.send(:set_field, self._name, { :type => self.field_type })
+    object.class_eval <<-EOF
+      alias :#{self._alias} :#{self._name}
+    EOF
+  end
+  
+  protected
+  
+  # def add_to_list_bottom
+  #   self.position = (self.siblings.map(&:position).max || 0) + 1
+  # end
+  
+  def set_unique_name!
+    self._name = "custom_field_#{self.increment_counter!}"
+  end
+    
+  def set_alias
+    return if self.label.blank? && self._alias.blank?
+    puts "set_alias !!!"
+    self._alias ||= self.label.clone
+    self._alias.slugify!(:downcase => true, :underscore => true)
+  end
+  
+  def increment_counter!
+    next_value = self._parent.send(:"#{self.association_name}_counter") + 1
+    self._parent.send(:"#{self.association_name}_counter=", next_value)
+    next_value
+  end
+  
+  def siblings
+    self._parent.associations[self.association_name]
+  end
+end
\ No newline at end of file
diff --git a/config/initializers/custom_fields.rb b/config/initializers/custom_fields.rb
new file mode 100644
index 00000000..4afded8c
--- /dev/null
+++ b/config/initializers/custom_fields.rb
@@ -0,0 +1,73 @@
+# encoding: utf-8
+module Mongoid #:nodoc:
+  module Associations #:nodoc:
+    class Options #:nodoc:
+      def custom_fields
+        @attributes[:custom_fields] == true
+      end
+    end
+  end
+end
+
+# encoding: utf-8
+module Mongoid #:nodoc:
+  module Associations #:nodoc:
+    class EmbedsMany < Proxy
+      def build_with_custom_field_settings(attrs = {}, type = nil)
+        document = build_without_custom_field_settings(attrs, type)
+        if self.target_custom_field_association?
+          document.send(:set_unique_name!)
+          document.send(:set_alias)
+        end
+        document
+      end
+      
+      alias_method_chain :build, :custom_field_settings
+      
+      def target_custom_field_association?
+        target_name = @association_name.gsub(/_fields$/, '').pluralize
+        # puts "target_name = #{target_name} / #{@parent.associations.key?(target_name).inspect} / #{@parent.inspect} / #{@parent.associations.inspect}"
+        if @parent.associations.key?(target_name)
+          @parent.associations[target_name].options.custom_fields
+        end
+      end
+      
+    end
+    
+  end
+end
+
+# encoding: utf-8
+module Mongoid #:nodoc:
+  module Document
+    module InstanceMethods
+      def parentize_with_custom_fields(object, association_name)
+        # puts "...parentize_with_custom_fields...#{self.inspect} - #{object.inspect} - #{association_name}"
+        parentize_without_custom_fields(object, association_name)
+        
+        if self.custom_fields?(object, association_name)
+          # puts "custom fields = #{object.asset_fields.inspect}"
+          puts "(((((((("
+          object.send(self.custom_fields_association_name(association_name)).each do |field|
+            # puts "field = #{field.inspect}"
+            # self.class.send(:set_field, field.name, { :type => field.field_type })
+            field.apply(self, association_name)
+          end
+          puts "))))))))"
+        end
+      end
+      
+      alias_method_chain :parentize, :custom_fields
+      
+      def custom_fields_association_name(association_name)
+        "#{association_name.singularize}_fields".to_sym
+      end
+      
+      def custom_fields?(object, association_name)
+        object.respond_to?(custom_fields_association_name(association_name)) &&
+        object.associations[association_name] && 
+        object.associations[association_name].options.custom_fields
+      end      
+    end    
+  end
+end
\ No newline at end of file
diff --git a/doc/TODO b/doc/TODO
index 750b9105..597e0987 100644
--- a/doc/TODO
+++ b/doc/TODO
@@ -49,6 +49,13 @@ x domain scoping when authenticating
   - custom resizing
 - assets uploader:
   - remove old files if new one
+- custom fields:
+	- renaming fields
+	- ui
+	- rename asset_field
+	- apply in asset_field
+	- extract a plugin from custom fields
+	- field position
 
 BACKLOG:
 - liquid rendering engine
diff --git a/spec/factories.rb b/spec/factories.rb
index 0f820b5e..56d0b937 100644
--- a/spec/factories.rb
+++ b/spec/factories.rb
@@ -61,4 +61,10 @@ end
 ## Theme assets ##
 Factory.define :theme_asset do |a|
   a.association :site
-end
\ No newline at end of file
+end
+
+## Asset collection ##
+Factory.define :asset_collection do |s|
+  s.association :site, :factory => :site
+  s.name 'Trip to Chicago'
+end
diff --git a/spec/models/asset_collections_spec.rb b/spec/models/asset_collections_spec.rb
new file mode 100644
index 00000000..e89400d1
--- /dev/null
+++ b/spec/models/asset_collections_spec.rb
@@ -0,0 +1,106 @@
+require 'spec_helper'
+ 
+describe AssetCollection do
+  
+  it 'should have a valid factory' do
+    Factory.build(:asset_collection).should be_valid
+  end
+  
+  describe 'custom fields (beta)' do
+    
+    before(:each) do
+      @collection = Factory.build(:asset_collection)
+      @collection.asset_fields.build :label => 'My Description', :_alias => 'description', :kind => 'Text'
+      @collection.asset_fields.build :label => 'Active', :kind => 'Boolean'
+    end
+    
+    context 'define attributes' do
+            
+      # it 'should have an unique name' do
+      #   @collection.asset_fields.first._name.should == "custom_field_1"
+      #   @collection.asset_fields.last._name.should == "custom_field_2"        
+      # end    
+      
+      it 'should have an unique alias' do
+        @collection.save
+        @collection.asset_fields.first._alias.should == "description"
+        @collection.asset_fields.last._alias.should == "active"
+      end  
+      
+      # 
+      # it 'should define a position according to siblings'   
+      
+    end
+    
+    # context 'build and save' do
+    # 
+    #   it 'should build asset' do
+    #     asset = @collection.assets.build
+    #     lambda {
+    #       asset.description
+    #       asset.active
+    #     }.should_not raise_error
+    #   end
+    #   
+    #   it 'should assign values to newly built asset' do
+    #     asset = build_asset(@collection)
+    #     asset.description.should == 'Lorem ipsum'
+    #     asset.active.should == true
+    #   end
+    # 
+    #   it 'should save asset' do
+    #     asset = build_asset(@collection)
+    #     asset.save and @collection.reload
+    #     asset = @collection.assets.first
+    #     asset.description.should == 'Lorem ipsum'
+    #     asset.active.should == true
+    #   end
+    #   
+    #   it 'should not modify assets from another collection' do
+    #     asset = build_asset(@collection)
+    #     asset.save and @collection.reload
+    #     new_collection = AssetCollection.new
+    #     lambda { new_collection.assets.build.description }.should raise_error
+    #   end
+    # 
+    # end
+    # 
+    context 'modifying fields' do
+      
+      # before(:each) do
+      #   @asset = build_asset(@collection).save
+      # end
+      # 
+      # it 'should add new field' do
+      #   @collection.asset_fields.build :label => 'Active at', :name => 'active_at', :kind => 'Date'
+      #   @collection.save
+      #   
+      #   # puts "association = #{@collection.send(:associations)['assets'].options.inspect}"
+      #   
+      #   # @collection = AssetCollection.first
+      #   # @collection.flush_cache(:asset_fields)
+      #   @collection.reload
+      #   # puts "# fields #{@collection.asset_fields.size.inspect}"  
+      #   # puts "============================"
+      #   # puts "@collection asset fields ==> #{@collection.asset_fields.inspect}"
+      #   asset = @collection.assets.first
+      #   lambda { asset.active_at }.should_not raise_error
+      # end
+      
+      # it 'should remove field' do
+      #   @collection.asset_fields.delete_all :name => 'active'
+      #   @collection.save
+      #   lambda { asset.active }.should raise_error
+      # end
+      # 
+      # it 'should be able to change field name'
+      
+    end
+    
+  end
+  
+  def build_asset(collection)
+    collection.assets.build(:name => 'Asset on steroids', :description => 'Lorem ipsum', :active => true)
+  end
+  
+end
\ No newline at end of file