diff --git a/src/_autoload.php b/src/_autoload.php
new file mode 100644
index 0000000..c8a7111
--- /dev/null
+++ b/src/_autoload.php
@@ -0,0 +1,39 @@
+<?php
+/*
+ * Copyright (c) 2014-2015, Jørn Åne de Jong <@jornane>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/**
+ * Register SPL autoloading for classes and interfaces.  Put this file in your
+ * namespace root and make sure it gets included from your PHP entry-point.
+ *
+ * There is no requirement for capitalisation for your namespaces and classes,
+ * but all folders and files MUST be lower-case.  Class names are automatically
+ * lower-cased on autoload.  This conforms to the PHP design philosophy that
+ * functions and class names must be case-insensitive.
+ *
+ * The include path is changed to prefer the current directory over the
+ * established include path.  This is because manual include/require statements
+ * will likely not be used, because it will be handled by autoloading.
+ * Feel free to change this behaviour if that works better for you.
+ *
+ * @author Jørn Åne de Jong <@jornane>
+ * @copyright Copyright (c) 2014-2015, Jørn Åne de Jong <@jornane>
+ * @link https://gist.github.com/jornane/667f2e3acc262ce6bf44
+ * @link http://php.net/manual/en/function.spl-autoload.php
+ * @license http://choosealicense.com/licenses/isc/ ISC license
+ */
+spl_autoload_extensions( '.php' );
+spl_autoload_register( 'spl_autoload' );
+set_include_path( realpath( __DIR__ ) . PATH_SEPARATOR . get_include_path() );
diff --git a/src/pvv/side/activity.php b/src/pvv/side/activity.php
new file mode 100644
index 0000000..8d81dcc
--- /dev/null
+++ b/src/pvv/side/activity.php
@@ -0,0 +1,14 @@
+<?php declare(strict_types=1);
+namespace pvv\side;
+
+use \DateTime;
+
+interface Activity {
+
+	public function getName(); /* : string */
+
+	public function getLocation(); /* : Location */
+
+	public function getOrganiser(); /* : User */
+
+}
diff --git a/src/pvv/side/event.php b/src/pvv/side/event.php
new file mode 100644
index 0000000..c00904c
--- /dev/null
+++ b/src/pvv/side/event.php
@@ -0,0 +1,10 @@
+<?php declare(strict_types=1);
+namespace pvv\side;
+
+interface Event extends Activity {
+
+	public function getStart(); /* : DateTime */
+
+	public function getStop(); /* : DateTime */
+
+}
diff --git a/src/pvv/side/repeatingactivity.php b/src/pvv/side/repeatingactivity.php
new file mode 100644
index 0000000..d1a60c9
--- /dev/null
+++ b/src/pvv/side/repeatingactivity.php
@@ -0,0 +1,12 @@
+<?php declare(strict_types=1);
+namespace pvv\side;
+
+use \DateTime;
+
+interface RepeatingActivity extends Activity {
+
+	public function getNextEventFrom(DateTime $date) /* : Event */;
+
+	public function getPreviousEventFrom(DateTime $date) /* : Event */;
+
+}