diff --git a/demo/moulinrouge/__init__.py b/demo/moulinrouge/__init__.py
index 4d1f644..16c1bae 100644
--- a/demo/moulinrouge/__init__.py
+++ b/demo/moulinrouge/__init__.py
@@ -21,6 +21,7 @@ from logging import getLogger, INFO, DEBUG
 import pygal
 from pygal.config import Config
 from pygal.util import cut
+from pygal.graph import CHARTS_NAMES
 from pygal.style import styles
 from base64 import (
     urlsafe_b64encode as b64encode,
@@ -33,9 +34,9 @@ import pickle
 def random_label():
     chars = string.letters + string.digits + u' àéèçêâäëï'
     return ''.join(
-            [random.choice(chars)
-             for i in range(
-                     random.randrange(4, 30))])
+        [random.choice(chars)
+         for i in range(
+                 random.randrange(4, 30))])
 
 
 def random_value(min=0, max=15):
@@ -72,7 +73,7 @@ def create_app():
                 values = [(
                     random_value((-max, min)[random.randrange(0, 2)], max),
                     random_value((-max, min)[random.randrange(0, 2)], max))
-                          for i in range(data)]
+                    for i in range(data)]
             else:
                 values = [random_value((-max, min)[random.randrange(1, 2)],
                                        max) for i in range(data)]
@@ -84,7 +85,9 @@ def create_app():
 
     @app.route("/")
     def index():
-        return render_template('index.jinja2', styles=styles, links=links)
+        return render_template(
+            'index.jinja2', styles=styles,
+            links=links, charts_name=CHARTS_NAMES)
 
     @app.route("/svg/<type>/<series>/<config>")
     def svg(type, series, config):
@@ -179,5 +182,4 @@ def create_app():
                                svgs=svgs,
                                width=width,
                                height=height)
-    
     return app
diff --git a/demo/moulinrouge/templates/index.jinja2 b/demo/moulinrouge/templates/index.jinja2
index 8888c97..9b8c700 100644
--- a/demo/moulinrouge/templates/index.jinja2
+++ b/demo/moulinrouge/templates/index.jinja2
@@ -13,7 +13,17 @@
   <h3>Quick tests</h3>
   <dl>
     {% for link in links %}
-      <dd><a href="{{ url_for(link) }}">{{ link.replace('test_', '').replace('_', ' ') | title }}</a></dd>
+      {% if link.endswith('_for') %}
+        <dd>{{ link.replace('test_', '').replace('_for', '').replace('_', ' ') | title }}
+          <small>
+        {% for chart_name in charts_name %}
+          <a href="{{ url_for(link, chart=chart_name) }}">{{ chart_name | title }}</a>
+        {% endfor %}
+          </small>
+        </dd>
+      {% else %}
+        <dd><a href="{{ url_for(link) }}">{{ link.replace('test_', '').replace('_', ' ') | title }}</a></dd>
+    {% endif %}
     {% endfor %}
   </dl>
 {% endblock section %}
diff --git a/demo/moulinrouge/tests.py b/demo/moulinrouge/tests.py
index 667ef2a..494dd88 100644
--- a/demo/moulinrouge/tests.py
+++ b/demo/moulinrouge/tests.py
@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
 # This file is part of pygal
-import pygal
-from pygal import Bar, Gauge, Pyramid, Funnel, Dot
+from pygal import Bar, Gauge, Pyramid, Funnel, Dot, CHARTS_BY_NAME
 from pygal.style import styles
 
 
@@ -98,4 +97,11 @@ def get_test_routes(app):
 
         return dot.render_response()
 
+    @app.route('/test/interpolate/<chart>')
+    def test_interpolate_for(chart):
+        graph = CHARTS_BY_NAME[chart](interpolate='cubic')
+        graph.add('1', [1, 3, 12, 3, 4])
+        graph.add('2', [7, -4, 10, None, 8, 3, 1])
+        return graph.render_response()
+
     return filter(lambda x: x.startswith('test'), locals())
diff --git a/pygal/__init__.py b/pygal/__init__.py
index 4b28da7..ee19346 100644
--- a/pygal/__init__.py
+++ b/pygal/__init__.py
@@ -28,11 +28,13 @@ from pygal.ghost import Ghost
 from pygal.graph import CHARTS_NAMES
 
 CHARTS = []
+CHARTS_BY_NAME = {}
 
 for NAME in CHARTS_NAMES:
     _CHART = type(NAME, (Ghost,), {})
     CHARTS.append(_CHART)
+    CHARTS_BY_NAME[NAME] = _CHART
     setattr(sys.modules[__name__], NAME, _CHART)
 
 
-__all__ = CHARTS_NAMES + [Config.__name__, 'CHARTS']
+__all__ = CHARTS_NAMES + [Config.__name__, 'CHARTS', 'CHARTS_BY_NAME']
diff --git a/pygal/test/test_config.py b/pygal/test/test_config.py
index 7d5073d..869136f 100644
--- a/pygal/test/test_config.py
+++ b/pygal/test/test_config.py
@@ -144,6 +144,14 @@ def test_logarithmic():
     assert len(q(".dots")) == 3
 
 
+def test_interpolation(Chart):
+    chart = Chart(interpolate='cubic')
+    chart.add('1', [1, 3, 12, 3, 4])
+    chart.add('2', [7, -4, 10, None, 8, 3, 1])
+    q = chart.render_pyquery()
+    assert len(q(".legend")) == 2
+
+
 def test_logarithmic_bad_interpolation():
     try:
         import scipy