diff --git a/resources/sql/autopatches/20161104.calendar.01.availability.sql b/resources/sql/autopatches/20161104.calendar.01.availability.sql
new file mode 100644
index 0000000000..cb64339df2
--- /dev/null
+++ b/resources/sql/autopatches/20161104.calendar.01.availability.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_calendar.calendar_eventinvitee
+  ADD availability VARCHAR(64) NOT NULL;
diff --git a/resources/sql/autopatches/20161104.calendar.02.availdefault.sql b/resources/sql/autopatches/20161104.calendar.02.availdefault.sql
new file mode 100644
index 0000000000..12a42f711a
--- /dev/null
+++ b/resources/sql/autopatches/20161104.calendar.02.availdefault.sql
@@ -0,0 +1,3 @@
+UPDATE {$NAMESPACE}_calendar.calendar_eventinvitee
+  SET availability = 'default'
+  WHERE availability = '';
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index 46069785a6..4c6fb41333 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -2035,6 +2035,7 @@ phutil_register_library_map(array(
     'PhabricatorCalendarEvent' => 'applications/calendar/storage/PhabricatorCalendarEvent.php',
     'PhabricatorCalendarEventAcceptTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventAcceptTransaction.php',
     'PhabricatorCalendarEventAllDayTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventAllDayTransaction.php',
+    'PhabricatorCalendarEventAvailabilityController' => 'applications/calendar/controller/PhabricatorCalendarEventAvailabilityController.php',
     'PhabricatorCalendarEventCancelController' => 'applications/calendar/controller/PhabricatorCalendarEventCancelController.php',
     'PhabricatorCalendarEventCancelTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventCancelTransaction.php',
     'PhabricatorCalendarEventDateTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventDateTransaction.php',
@@ -6881,6 +6882,7 @@ phutil_register_library_map(array(
     ),
     'PhabricatorCalendarEventAcceptTransaction' => 'PhabricatorCalendarEventReplyTransaction',
     'PhabricatorCalendarEventAllDayTransaction' => 'PhabricatorCalendarEventTransactionType',
+    'PhabricatorCalendarEventAvailabilityController' => 'PhabricatorCalendarController',
     'PhabricatorCalendarEventCancelController' => 'PhabricatorCalendarController',
     'PhabricatorCalendarEventCancelTransaction' => 'PhabricatorCalendarEventTransactionType',
     'PhabricatorCalendarEventDateTransaction' => 'PhabricatorCalendarEventTransactionType',
diff --git a/src/applications/calendar/application/PhabricatorCalendarApplication.php b/src/applications/calendar/application/PhabricatorCalendarApplication.php
index 8caf8c27ec..fa534280a0 100644
--- a/src/applications/calendar/application/PhabricatorCalendarApplication.php
+++ b/src/applications/calendar/application/PhabricatorCalendarApplication.php
@@ -61,6 +61,8 @@ final class PhabricatorCalendarApplication extends PhabricatorApplication {
             => 'PhabricatorCalendarEventJoinController',
           'export/(?P<id>[1-9]\d*)/(?P<filename>[^/]*)'
             => 'PhabricatorCalendarEventExportController',
+          'availability/(?P<id>[1-9]\d*)/(?P<availability>[^/]+)/'
+            => 'PhabricatorCalendarEventAvailabilityController',
         ),
         'export/' => array(
           $this->getQueryRoutePattern()
diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventAvailabilityController.php b/src/applications/calendar/controller/PhabricatorCalendarEventAvailabilityController.php
new file mode 100644
index 0000000000..04a2454a0f
--- /dev/null
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventAvailabilityController.php
@@ -0,0 +1,56 @@
+<?php
+
+final class PhabricatorCalendarEventAvailabilityController
+  extends PhabricatorCalendarController {
+
+  public function handleRequest(AphrontRequest $request) {
+    $viewer = $this->getViewer();
+    $id = $request->getURIData('id');
+
+    $event = id(new PhabricatorCalendarEventQuery())
+      ->setViewer($viewer)
+      ->withIDs(array($id))
+      ->executeOne();
+    if (!$event) {
+      return new Aphront404Response();
+    }
+
+    $response = $this->newImportedEventResponse($event);
+    if ($response) {
+      return $response;
+    }
+
+    $cancel_uri = $event->getURI();
+
+    if (!$event->getIsUserAttending($viewer->getPHID())) {
+      return $this->newDialog()
+        ->setTitle(pht('Not Attending Event'))
+        ->appendParagraph(
+          pht(
+            'You can not change your display availability for events you '.
+            'are not attending.'))
+        ->addCancelButton($cancel_uri);
+    }
+
+    // TODO: This endpoint currently only works via AJAX. It would be vaguely
+    // nice to provide a plain HTML version of the workflow where we return
+    // a dialog with a vanilla <select /> in it for cases where all the JS
+    // breaks.
+    $request->validateCSRF();
+
+    $invitee = $event->getInviteeForPHID($viewer->getPHID());
+
+    $map = PhabricatorCalendarEventInvitee::getAvailabilityMap();
+    $new_availability = $request->getURIData('availability');
+    if (isset($map[$new_availability])) {
+      $invitee
+        ->setAvailability($new_availability)
+        ->save();
+
+      // Invalidate the availability cache.
+      $viewer->writeAvailabilityCache(array(), null);
+    }
+
+    return id(new AphrontRedirectResponse())->setURI($cancel_uri);
+  }
+}
diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php b/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php
index a003611886..b5b1c0cc48 100644
--- a/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php
@@ -132,6 +132,43 @@ final class PhabricatorCalendarEventViewController
       $header->addActionLink($action);
     }
 
+    $options = PhabricatorCalendarEventInvitee::getAvailabilityMap();
+
+    $is_attending = $event->getIsUserAttending($viewer->getPHID());
+    if ($is_attending) {
+      $invitee = $event->getInviteeForPHID($viewer->getPHID());
+
+      $selected = $invitee->getDisplayAvailability($event);
+      if (!$selected) {
+        $selected = PhabricatorCalendarEventInvitee::AVAILABILITY_AVAILABLE;
+      }
+
+      $selected_option = idx($options, $selected);
+
+      $availability_select = id(new PHUIButtonView())
+        ->setTag('a')
+        ->setIcon('fa-circle '.$selected_option['color'])
+        ->setText(pht('Availability: %s', $selected_option['name']));
+
+      $dropdown = id(new PhabricatorActionListView())
+        ->setUser($viewer);
+
+      foreach ($options as $key => $option) {
+        $uri = "event/availability/{$id}/{$key}/";
+        $uri = $this->getApplicationURI($uri);
+
+        $dropdown->addAction(
+          id(new PhabricatorActionView())
+            ->setName($option['name'])
+            ->setIcon('fa-circle '.$option['color'])
+            ->setHref($uri)
+            ->setWorkflow(true));
+      }
+
+      $availability_select->setDropdownMenu($dropdown);
+      $header->addActionLink($availability_select);
+    }
+
     return $header;
   }
 
diff --git a/src/applications/calendar/storage/PhabricatorCalendarEvent.php b/src/applications/calendar/storage/PhabricatorCalendarEvent.php
index 440e35f980..1d0f88cc3c 100644
--- a/src/applications/calendar/storage/PhabricatorCalendarEvent.php
+++ b/src/applications/calendar/storage/PhabricatorCalendarEvent.php
@@ -448,6 +448,12 @@ final class PhabricatorCalendarEvent extends PhabricatorCalendarDAO
     return $this->assertAttached($this->invitees);
   }
 
+  public function getInviteeForPHID($phid) {
+    $invitees = $this->getInvitees();
+    $invitees = mpull($invitees, null, 'getInviteePHID');
+    return idx($invitees, $phid);
+  }
+
   public static function getFrequencyMap() {
     return array(
       PhutilCalendarRecurrenceRule::FREQUENCY_DAILY => array(
diff --git a/src/applications/calendar/storage/PhabricatorCalendarEventInvitee.php b/src/applications/calendar/storage/PhabricatorCalendarEventInvitee.php
index b1d2b2d34c..34d4c85fcf 100644
--- a/src/applications/calendar/storage/PhabricatorCalendarEventInvitee.php
+++ b/src/applications/calendar/storage/PhabricatorCalendarEventInvitee.php
@@ -7,12 +7,18 @@ final class PhabricatorCalendarEventInvitee extends PhabricatorCalendarDAO
   protected $inviteePHID;
   protected $inviterPHID;
   protected $status;
+  protected $availability = self::AVAILABILITY_DEFAULT;
 
   const STATUS_INVITED = 'invited';
   const STATUS_ATTENDING = 'attending';
   const STATUS_DECLINED = 'declined';
   const STATUS_UNINVITED = 'uninvited';
 
+  const AVAILABILITY_DEFAULT = 'default';
+  const AVAILABILITY_AVAILABLE = 'available';
+  const AVAILABILITY_BUSY = 'busy';
+  const AVAILABILITY_AWAY = 'away';
+
   public static function initializeNewCalendarEventInvitee(
     PhabricatorUser $actor, $event) {
     return id(new PhabricatorCalendarEventInvitee())
@@ -25,6 +31,7 @@ final class PhabricatorCalendarEventInvitee extends PhabricatorCalendarDAO
     return array(
       self::CONFIG_COLUMN_SCHEMA => array(
         'status' => 'text64',
+        'availability' => 'text64',
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'key_event' => array(
@@ -50,6 +57,50 @@ final class PhabricatorCalendarEventInvitee extends PhabricatorCalendarDAO
     }
   }
 
+  public function getDisplayAvailability(PhabricatorCalendarEvent $event) {
+    switch ($this->getAvailability()) {
+      case self::AVAILABILITY_DEFAULT:
+      case self::AVAILABILITY_BUSY:
+        return self::AVAILABILITY_BUSY;
+      case self::AVAILABILITY_AWAY:
+        return self::AVAILABILITY_AWAY;
+      default:
+        return null;
+    }
+  }
+
+  public static function getAvailabilityMap() {
+    return array(
+      self::AVAILABILITY_AVAILABLE => array(
+        'color' => 'green',
+        'name' => pht('Available'),
+      ),
+      self::AVAILABILITY_BUSY => array(
+        'color' => 'yellow',
+        'name' => pht('Busy'),
+      ),
+      self::AVAILABILITY_AWAY => array(
+        'color' => 'red',
+        'name' => pht('Away'),
+      ),
+    );
+  }
+
+  public static function getAvailabilitySpec($const) {
+    return idx(self::getAvailabilityMap(), $const, array());
+  }
+
+  public static function getAvailabilityName($const) {
+    $spec = self::getAvailabilitySpec($const);
+    return idx($spec, 'name', $const);
+  }
+
+  public static function getAvailabilityColor($const) {
+    $spec = self::getAvailabilitySpec($const);
+    return idx($spec, 'color', 'indigo');
+  }
+
+
 /* -(  PhabricatorPolicyInterface  )----------------------------------------- */
 
 
diff --git a/src/applications/calendar/view/PHUIUserAvailabilityView.php b/src/applications/calendar/view/PHUIUserAvailabilityView.php
index 57583118c4..7ab0ace77a 100644
--- a/src/applications/calendar/view/PHUIUserAvailabilityView.php
+++ b/src/applications/calendar/view/PHUIUserAvailabilityView.php
@@ -23,16 +23,57 @@ final class PHUIUserAvailabilityView
       return pht('Available');
     }
 
+    $const = $user->getDisplayAvailability();
+    $name = PhabricatorCalendarEventInvitee::getAvailabilityName($const);
+    $color = PhabricatorCalendarEventInvitee::getAvailabilityColor($const);
+
     $away_tag = id(new PHUITagView())
       ->setType(PHUITagView::TYPE_SHADE)
-      ->setShade(PHUITagView::COLOR_RED)
-      ->setName(pht('Away'))
-      ->setDotColor(PHUITagView::COLOR_RED);
+      ->setShade($color)
+      ->setName($name)
+      ->setDotColor($color);
 
     $now = PhabricatorTime::getNow();
-    $description = pht(
-      'Away until %s',
-      $viewer->formatShortDateTime($until, $now));
+
+    // Try to load the event handle. If it's invalid or the user can't see it,
+    // we'll just render a generic message.
+    $object_phid = $user->getAvailabilityEventPHID();
+    $handle = null;
+    if ($object_phid) {
+      $handles = $viewer->loadHandles(array($object_phid));
+      $handle = $handles[$object_phid];
+      if (!$handle->isComplete() || $handle->getPolicyFiltered()) {
+        $handle = null;
+      }
+    }
+
+    switch ($const) {
+      case PhabricatorCalendarEventInvitee::AVAILABILITY_AWAY:
+        if ($handle) {
+          $description = pht(
+            'Away at %s until %s.',
+            $handle->renderLink(),
+            $viewer->formatShortDateTime($until, $now));
+        } else {
+          $description = pht(
+            'Away until %s.',
+            $viewer->formatShortDateTime($until, $now));
+        }
+        break;
+      case PhabricatorCalendarEventInvitee::AVAILABILITY_BUSY:
+      default:
+        if ($handle) {
+          $description = pht(
+            'Busy at %s until %s.',
+            $handle->renderLink(),
+            $viewer->formatShortDateTime($until, $now));
+        } else {
+          $description = pht(
+            'Busy until %s.',
+            $viewer->formatShortDateTime($until, $now));
+        }
+        break;
+    }
 
     return array(
       $away_tag,
diff --git a/src/applications/people/phid/PhabricatorPeopleUserPHIDType.php b/src/applications/people/phid/PhabricatorPeopleUserPHIDType.php
index 40159d1cc2..77e0088c5e 100644
--- a/src/applications/people/phid/PhabricatorPeopleUserPHIDType.php
+++ b/src/applications/people/phid/PhabricatorPeopleUserPHIDType.php
@@ -66,7 +66,12 @@ final class PhabricatorPeopleUserPHIDType extends PhabricatorPHIDType {
       } else {
         $until = $user->getAwayUntil();
         if ($until) {
-          $availability = PhabricatorObjectHandle::AVAILABILITY_NONE;
+          $away = PhabricatorCalendarEventInvitee::AVAILABILITY_AWAY;
+          if ($user->getDisplayAvailability() == $away) {
+            $availability = PhabricatorObjectHandle::AVAILABILITY_NONE;
+          } else {
+            $availability = PhabricatorObjectHandle::AVAILABILITY_PARTIAL;
+          }
         }
       }
 
diff --git a/src/applications/people/query/PhabricatorPeopleQuery.php b/src/applications/people/query/PhabricatorPeopleQuery.php
index 07fbc8b941..88e2437dbd 100644
--- a/src/applications/people/query/PhabricatorPeopleQuery.php
+++ b/src/applications/people/query/PhabricatorPeopleQuery.php
@@ -395,18 +395,28 @@ final class PhabricatorPeopleQuery
     // Group all the events by invited user. Only examine events that users
     // are actually attending.
     $map = array();
+    $invitee_map = array();
     foreach ($events as $event) {
       foreach ($event->getInvitees() as $invitee) {
         if (!$invitee->isAttending()) {
           continue;
         }
 
+        // If the user is set to "Available" for this event, don't consider it
+        // when computin their away status.
+        if (!$invitee->getDisplayAvailability($event)) {
+          continue;
+        }
+
         $invitee_phid = $invitee->getInviteePHID();
         if (!isset($rebuild[$invitee_phid])) {
           continue;
         }
 
         $map[$invitee_phid][] = $event;
+
+        $event_phid = $event->getPHID();
+        $invitee_map[$invitee_phid][$event_phid] = $invitee;
       }
     }
 
@@ -426,6 +436,7 @@ final class PhabricatorPeopleQuery
       }
 
       $cursor = $min_range;
+      $next_event = null;
       if ($events) {
         // Find the next time when the user has no meetings. If we move forward
         // because of an event, we check again for events after that one ends.
@@ -435,6 +446,9 @@ final class PhabricatorPeopleQuery
             $to = $event->getEndDateTimeEpoch();
             if (($from <= $cursor) && ($to > $cursor)) {
               $cursor = $to;
+              if (!$next_event) {
+                $next_event = $event;
+              }
               continue 2;
             }
           }
@@ -443,13 +457,29 @@ final class PhabricatorPeopleQuery
       }
 
       if ($cursor > $min_range) {
+        $invitee = $invitee_map[$phid][$next_event->getPHID()];
+        $availability_type = $invitee->getDisplayAvailability($next_event);
         $availability = array(
           'until' => $cursor,
+          'eventPHID' => $event->getPHID(),
+          'availability' => $availability_type,
         );
-        $availability_ttl = $cursor;
+
+        // We only cache this availability until the end of the current event,
+        // since the event PHID (and possibly the availability type) are only
+        // valid for that long.
+
+        // NOTE: This doesn't handle overlapping events with the greatest
+        // possible care. In theory, if you're attenting multiple events
+        // simultaneously we should accommodate that. However, it's complex
+        // to compute, rare, and probably not confusing most of the time.
+
+        $availability_ttl = $next_event->getStartDateTimeEpochForCache();
       } else {
         $availability = array(
           'until' => null,
+          'eventPHID' => null,
+          'availability' => null,
         );
         $availability_ttl = $max_range;
       }
diff --git a/src/applications/people/storage/PhabricatorUser.php b/src/applications/people/storage/PhabricatorUser.php
index b7a384a149..ef2046c21e 100644
--- a/src/applications/people/storage/PhabricatorUser.php
+++ b/src/applications/people/storage/PhabricatorUser.php
@@ -960,6 +960,32 @@ final class PhabricatorUser
   }
 
 
+  public function getDisplayAvailability() {
+    $availability = $this->availability;
+
+    $this->assertAttached($availability);
+    if (!$availability) {
+      return null;
+    }
+
+    $busy = PhabricatorCalendarEventInvitee::AVAILABILITY_BUSY;
+
+    return idx($availability, 'availability', $busy);
+  }
+
+
+  public function getAvailabilityEventPHID() {
+    $availability = $this->availability;
+
+    $this->assertAttached($availability);
+    if (!$availability) {
+      return null;
+    }
+
+    return idx($availability, 'eventPHID');
+  }
+
+
   /**
    * Get cached availability, if present.
    *