diff --git a/lib/google_visualr.rb b/lib/google_visualr.rb
index 626f747..3415433 100644
--- a/lib/google_visualr.rb
+++ b/lib/google_visualr.rb
@@ -38,6 +38,7 @@
 require "#{lib_path}/google_visualr/interactive/motion_chart"
 require "#{lib_path}/google_visualr/interactive/org_chart"
 require "#{lib_path}/google_visualr/interactive/timeline"
+require "#{lib_path}/google_visualr/interactive/calendar"
 
 # Image Charts
 require "#{lib_path}/google_visualr/image/spark_line"
diff --git a/lib/google_visualr/base_chart.rb b/lib/google_visualr/base_chart.rb
index cf7743d..5ea2e11 100644
--- a/lib/google_visualr/base_chart.rb
+++ b/lib/google_visualr/base_chart.rb
@@ -4,12 +4,13 @@ class BaseChart
     include GoogleVisualr::Packages
     include GoogleVisualr::ParamHelpers
 
-    attr_accessor :data_table, :listeners
+    attr_accessor :data_table, :listeners, :functions
 
     def initialize(data_table, options={})
       @data_table = data_table
       send(:options=, options)
       @listeners  = []
+      @functions = []
     end
 
     def chart_name
@@ -32,6 +33,10 @@ def add_listener(event, callback)
       @listeners << { :event => event.to_s, :callback => callback }
     end
 
+    def add_function(callback)
+      @functions << { callback: callback }
+    end
+
     # Generates JavaScript and renders the Google Chart in the final HTML output.
     #
     # Parameters:
@@ -66,6 +71,9 @@ def draw_js(element_id)
         js << "\n    google.visualization.events.addListener(chart, '#{listener[:event]}', #{listener[:callback]});"
       end
       js << "\n    chart.draw(data_table, #{js_parameters(@options)});"
+      @functions.each do |efunction|
+        js << "\n\n #{efunction[:callback]}"
+      end
       js << "\n  };"
       js
     end
diff --git a/lib/google_visualr/interactive/calendar.rb b/lib/google_visualr/interactive/calendar.rb
new file mode 100644
index 0000000..2460f1d
--- /dev/null
+++ b/lib/google_visualr/interactive/calendar.rb
@@ -0,0 +1,11 @@
+module GoogleVisualr
+  module Interactive
+
+    # https://developers.google.com/chart/interactive/docs/gallery/timeline
+    class Calendar < BaseChart
+      # For Configuration Options, please refer to:
+      # https://developers.google.com/chart/interactive/docs/gallery/calendar#Overview
+    end
+
+  end
+end
diff --git a/spec/google_visualr/base_chart_spec.rb b/spec/google_visualr/base_chart_spec.rb
index cd87413..a42e65d 100644
--- a/spec/google_visualr/base_chart_spec.rb
+++ b/spec/google_visualr/base_chart_spec.rb
@@ -43,6 +43,14 @@
       @chart.listeners.should == [{ :event => "select", :callback => "function() {test_event(chart);}" }]
     end
   end
+  
+  describe '#add_function' do
+    it 'adds to embedded functions array' do
+      @chart.add_function("function() {alert(\"Nothing to see here\");}")
+      @chart.functions.should == [{ callback: "function()
+    {alert(\"Nothing to see here\");}" }]
+    end
+  end
 
   describe "#to_js" do
     it "generates JS" do