diff --git a/lib/magic_enum.rb b/lib/magic_enum.rb
index 20fe6ec..7ec3ac3 100644
--- a/lib/magic_enum.rb
+++ b/lib/magic_enum.rb
@@ -2,3 +2,4 @@
 require 'magic_enum/class_methods'
 
 ActiveRecord::Base.extend(MagicEnum::ClassMethods)
+ActiveResource::Base.extend(MagicEnum::ClassMethods) if defined?(::ActiveResource)
diff --git a/lib/magic_enum/class_methods.rb b/lib/magic_enum/class_methods.rb
index 23ba677..e2765f8 100644
--- a/lib/magic_enum/class_methods.rb
+++ b/lib/magic_enum/class_methods.rb
@@ -50,12 +50,12 @@ module ClassMethods
     #   StatusesInverted = Statuses.invert
     #
     #   def status
-    #     return StatusesInverted[self[:status].to_i] || StatusesInverted[1]
+    #     return StatusesInverted[self.attributes[:status].to_i] || StatusesInverted[1]
     #   end
     #
     #   def status=(value)
     #     raise ArgumentError, "Invalid value \"#{value}\" for :status attribute of the #{self.class} model" if Statuses[value].nil?
-    #     self[:status] = Statuses[value]
+    #     self.attributes[:status] = Statuses[value]
     #   end
     #
     #   def unknown?
@@ -98,12 +98,12 @@ def define_enum(name, opts = {})
         else
           a <=> b
         end
-      end.first unless opts[:default]
+      end.first unless opts.has_key?(:default)
 
       const_set(enum_inverted, const_get(enum).invert)
 
       define_method name do
-        self.class.const_get(enum_inverted)[self[name]] || self.class.const_get(enum_inverted)[opts[:default]]
+        self.class.const_get(enum_inverted)[self.attributes[name]] || self.class.const_get(enum_inverted)[opts[:default]]
       end
 
       define_method "#{name}_name" do
@@ -111,12 +111,12 @@ def define_enum(name, opts = {})
       end
 
       define_method "#{name}=" do |value|
-        value = value.to_sym if value.is_a?(String)
+        value = value.to_sym if value.is_a?(String) && value.length > 0
         raise ArgumentError, "Invalid value \"#{value}\" for :#{name} attribute of the #{self.class} model" if opts[:raise_on_invalid] and self.class.const_get(enum)[value].nil?
         if value.is_a?(Integer)
-          self[name] = value
+          self.attributes[name] = value
         else
-          self[name] = self.class.const_get(enum)[value] || opts[:default]
+          self.attributes[name] = self.class.const_get(enum)[value] || opts[:default]
         end
       end
 
diff --git a/spec/magic_enum_spec.rb b/spec/magic_enum_spec.rb
index 65343d1..b3362b7 100644
--- a/spec/magic_enum_spec.rb
+++ b/spec/magic_enum_spec.rb
@@ -2,10 +2,11 @@
 require 'active_record'
 
 require File.dirname(__FILE__) + '/../init'
+require File.dirname(__FILE__) + '/../lib/magic_enum'
 
 module MagicEnumHelper
   class TestModelBase
-    include MagicEnum
+    extend MagicEnum::ClassMethods
     Statuses = { :unknown => 0, :draft => 1, :published => 2 }
 
     def [](attr_name)
@@ -15,6 +16,12 @@ def [](attr_name)
     def []=(attr_name, value)
       @status = value
     end
+    attr_accessor :attributes
+
+    def initialize(*args)
+      super
+      @attributes = {}
+    end
   end
 end
 
@@ -52,6 +59,11 @@ class TestModel1 < MagicEnumHelper::TestModelBase
     @model.status.should == :unknown
   end
 
+  specify 'use a default value if the string is empty' do
+    @model.status = ''
+    @model[:status].should == 0
+  end
+    
   specify 'should store enum value if key is given as integer equivalent' do
     @model.status = 1
     @model[:status].should == 1
@@ -125,6 +137,25 @@ class TestModel2 < MagicEnumHelper::TestModelBase
   end
 end
 
+context 'Model with magic enum and default value of nil' do
+  include MagicEnumHelper
+
+  class TestModelNil < MagicEnumHelper::TestModelBase
+    define_enum :status, :default => nil
+  end
+
+  setup do
+    @model = TestModelNil.new
+  end
+
+  specify 'should use default value when current state is invalid' do
+    @model.status = :draft
+    @model.status.should == :draft
+    @model.status = nil
+    @model.status.should == nil
+  end
+end
+
 describe 'Model with magic enum and raise_on_invalid option specified' do
   include MagicEnumHelper