diff --git a/src/applications/calendar/controller/PhabricatorCalendarController.php b/src/applications/calendar/controller/PhabricatorCalendarController.php
--- a/src/applications/calendar/controller/PhabricatorCalendarController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarController.php
@@ -18,4 +18,23 @@
       ->setContent($ics_data);
   }
 
+  protected function newImportedEventResponse(PhabricatorCalendarEvent $event) {
+    if (!$event->isImportedEvent()) {
+      return null;
+    }
+
+    // Give the user a specific, detailed message if they try to edit an
+    // imported event via common web paths. Other edits (including those via
+    // the API) are blocked by the normal policy system, but this makes it more
+    // clear exactly why the event can't be edited.
+
+    return $this->newDialog()
+      ->setTitle(pht('Can Not Edit Imported Event'))
+      ->appendParagraph(
+        pht(
+          'This event has been imported from an external source and '.
+          'can not be edited.'))
+      ->addCancelButton($event->getURI(), pht('Done'));
+  }
+
 }
diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventCancelController.php b/src/applications/calendar/controller/PhabricatorCalendarEventCancelController.php
--- a/src/applications/calendar/controller/PhabricatorCalendarEventCancelController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventCancelController.php
@@ -7,19 +7,27 @@
     $viewer = $request->getViewer();
     $id = $request->getURIData('id');
 
+    // Just check CAN_VIEW first. Then we'll check if this is an import so
+    // we can raise a better error.
     $event = id(new PhabricatorCalendarEventQuery())
       ->setViewer($viewer)
       ->withIDs(array($id))
-      ->requireCapabilities(
-        array(
-          PhabricatorPolicyCapability::CAN_VIEW,
-          PhabricatorPolicyCapability::CAN_EDIT,
-        ))
       ->executeOne();
     if (!$event) {
       return new Aphront404Response();
     }
 
+    $response = $this->newImportedEventResponse($event);
+    if ($response) {
+      return $response;
+    }
+
+    // Now that we've done the import check, check for CAN_EDIT.
+    PhabricatorPolicyFilter::requireCapability(
+      $viewer,
+      $event,
+      PhabricatorPolicyCapability::CAN_EDIT);
+
     $cancel_uri = $event->getURI();
 
     $is_parent = $event->isParentEvent();
diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventEditController.php b/src/applications/calendar/controller/PhabricatorCalendarEventEditController.php
--- a/src/applications/calendar/controller/PhabricatorCalendarEventEditController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventEditController.php
@@ -4,6 +4,20 @@
   extends PhabricatorCalendarController {
 
   public function handleRequest(AphrontRequest $request) {
+    $viewer = $this->getViewer();
+
+    $id = $request->getURIData('id');
+    if ($id) {
+      $event = id(new PhabricatorCalendarEventQuery())
+        ->setViewer($viewer)
+        ->withIDs(array($id))
+        ->executeOne();
+      $response = $this->newImportedEventResponse($event);
+      if ($response) {
+        return $response;
+      }
+    }
+
     return id(new PhabricatorCalendarEventEditEngine())
       ->setController($this)
       ->buildResponse();
diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventJoinController.php b/src/applications/calendar/controller/PhabricatorCalendarEventJoinController.php
--- a/src/applications/calendar/controller/PhabricatorCalendarEventJoinController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventJoinController.php
@@ -15,6 +15,11 @@
       return new Aphront404Response();
     }
 
+    $response = $this->newImportedEventResponse($event);
+    if ($response) {
+      return $response;
+    }
+
     $cancel_uri = $event->getURI();
 
     $action = $request->getURIData('action');
diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php b/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php
--- a/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php
@@ -63,6 +63,19 @@
       ->setHeader(pht('Details'));
     $recurring_header = $this->buildRecurringHeader($event);
 
+    // NOTE: This is a bit hacky: for imported events, we're just hiding the
+    // comment form without actually preventing comments. Users could still
+    // submit a request to add comments to these events. This isn't really a
+    // major problem since they can't do anything truly bad and there isn't an
+    // easy way to selectively disable this or some other similar behaviors
+    // today, but it would probably be nice to fully disable these
+    // "pseudo-edits" (like commenting and probably subscribing and awarding
+    // tokens) at some point.
+    if ($event->isImportedEvent()) {
+      $comment_view = null;
+      $timeline->setShouldTerminate(true);
+    }
+
     $view = id(new PHUITwoColumnView())
       ->setHeader($header)
       ->setSubheader($subheader)
@@ -105,6 +118,16 @@
       ->setPolicyObject($event)
       ->setHeaderIcon($event->getIcon());
 
+    if ($event->isImportedEvent()) {
+      $header->addTag(
+        id(new PHUITagView())
+          ->setType(PHUITagView::TYPE_SHADE)
+          ->setName(pht('Imported'))
+          ->setIcon('fa-download')
+          ->setHref($event->getImportSource()->getURI())
+          ->setShade('orange'));
+    }
+
     foreach ($this->buildRSVPActions($event) as $action) {
       $header->addActionLink($action);
     }
@@ -141,12 +164,15 @@
           ->setWorkflow(!$can_edit));
     }
 
+    $can_attend = !$event->isImportedEvent();
+
     if ($is_attending) {
       $curtain->addAction(
         id(new PhabricatorActionView())
           ->setName(pht('Decline Event'))
           ->setIcon('fa-user-times')
           ->setHref($this->getApplicationURI("event/join/{$id}/"))
+          ->setDisabled(!$can_attend)
           ->setWorkflow(true));
     } else {
       $curtain->addAction(
@@ -154,6 +180,7 @@
           ->setName(pht('Join Event'))
           ->setIcon('fa-user-plus')
           ->setHref($this->getApplicationURI("event/join/{$id}/"))
+          ->setDisabled(!$can_attend)
           ->setWorkflow(true));
     }
 
@@ -261,6 +288,15 @@
         pht('None'));
     }
 
+    if ($event->isImportedEvent()) {
+      $properties->addProperty(
+        pht('Imported By'),
+        pht(
+          '%s from %s',
+          $viewer->renderHandle($event->getImportAuthorPHID()),
+          $viewer->renderHandle($event->getImportSourcePHID())));
+    }
+
     $properties->addProperty(
       pht('Invitees'),
       $invitee_list);
diff --git a/src/applications/calendar/phid/PhabricatorCalendarImportPHIDType.php b/src/applications/calendar/phid/PhabricatorCalendarImportPHIDType.php
--- a/src/applications/calendar/phid/PhabricatorCalendarImportPHIDType.php
+++ b/src/applications/calendar/phid/PhabricatorCalendarImportPHIDType.php
@@ -33,7 +33,7 @@
       $import = $objects[$phid];
 
       $id = $import->getID();
-      $name = $import->getName();
+      $name = $import->getDisplayName();
       $uri = $import->getURI();
 
       $handle
diff --git a/src/applications/calendar/storage/PhabricatorCalendarEvent.php b/src/applications/calendar/storage/PhabricatorCalendarEvent.php
--- a/src/applications/calendar/storage/PhabricatorCalendarEvent.php
+++ b/src/applications/calendar/storage/PhabricatorCalendarEvent.php
@@ -576,6 +576,10 @@
       }
     }
 
+    if ($this->isImportedEvent()) {
+      return 'fa-download';
+    }
+
     return $this->getIcon();
   }
 
@@ -584,6 +588,10 @@
       return 'red';
     }
 
+    if ($this->isImportedEvent()) {
+      return 'orange';
+    }
+
     if ($viewer->isLoggedIn()) {
       $status = $this->getUserInviteStatus($viewer->getPHID());
       switch ($status) {