--- a/ckanext/exampletheme/plugin.py
+++ b/ckanext/exampletheme/plugin.py
@@ -1,1 +1,86 @@
+import os
+from logging import getLogger
 
+from genshi.filters.transform import Transformer
+
+from ckan.plugins import implements, SingletonPlugin
+from ckan.plugins import IConfigurer
+from ckan.plugins import IGenshiStreamFilter
+from ckan.plugins import IRoutes
+
+log = getLogger(__name__)
+
+
+class ExampleThemePlugin(SingletonPlugin):
+    """This plugin demonstrates how a theme packaged as a CKAN
+    extension might extend CKAN behaviour.
+
+    In this case, we implement three extension interfaces:
+
+      - ``IConfigurer`` allows us to override configuration normally
+        found in the ``ini``-file.  Here we use it to specify the site
+        title, and to tell CKAN to look in this package for templates
+        and resources that customise the core look and feel.
+      - ``IGenshiStreamFilter`` allows us to filter and transform the
+        HTML stream just before it is rendered.  In this case we use
+        it to rename "frob" to "foobar"
+      - ``IRoutes`` allows us to add new URLs, or override existing
+        URLs.  In this example we use it to override the default
+        ``/register`` behaviour with a custom controller
+    """
+    implements(IConfigurer, inherit=True)
+    implements(IGenshiStreamFilter, inherit=True)
+    implements(IRoutes, inherit=True)
+
+    def update_config(self, config):
+        """This IConfigurer implementation causes CKAN to look in the
+        ```public``` and ```templates``` directories present in this
+        package for any customisations.
+
+        It also shows how to set the site title here (rather than in
+        the main site .ini file), and causes CKAN to use the
+        customised package form defined in ``package_form.py`` in this
+        directory.
+        """
+        here = os.path.dirname(__file__)
+        rootdir = os.path.dirname(os.path.dirname(here))
+        our_public_dir = os.path.join(rootdir, 'ckanext',
+                                      'exampletheme', 'theme', 'public')
+        template_dir = os.path.join(rootdir, 'ckanext',
+                                    'exampletheme', 'theme',
+        'templates')
+        # set our local template and resource overrides
+        config['extra_public_paths'] = ','.join([our_public_dir,
+                config.get('extra_public_paths', '')])
+        config['extra_template_paths'] = ','.join([template_dir,
+                config.get('extra_template_paths', '')])
+        # set the title
+        config['ckan.site_title'] = "An example CKAN theme"
+        # set the customised package form (see ``setup.py`` for entry point)
+        config['package_form'] = "example_form"
+
+    def filter(self, stream):
+        """Conform to IGenshiStreamFilter interface.
+
+        This example filter renames 'frob' to 'foobar' (this string is
+        found in the custom ``home/index.html`` template provided as
+        part of the package).
+        """
+        stream = stream | Transformer('//p[@id="examplething"]/text()')\
+                 .substitute(r'frob', r'foobar')
+        return stream
+
+    def before_map(self, map):
+        """This IRoutes implementation overrides the standard
+        ``/user/register`` behaviour with a custom controller.  You
+        might instead use it to provide a completely new page, for
+        example.
+
+        Note that we have also provided a custom register form
+        template at ``theme/templates/user/register.html``.
+        """
+        map.connect('/user/register',
+                    controller='ckanext.exampletheme.controller:CustomUserController',
+                    action='custom_register')
+        return map
+