diff -Naurw moodle-clean/moodle/local/db/access.php moodle-dev/local/db/access.php
--- moodle-clean/moodle/local/db/access.php	2009-05-13 12:42:19.000000000 +0100
+++ moodle-dev/local/db/access.php	2009-05-13 12:45:04.000000000 +0100
@@ -9,6 +9,16 @@
             'editingteacher' => CAP_ALLOW,
             'student' => CAP_ALLOW
         )
+    ),
+    'moodle/calendar:view' => array(
+
+        'captype' => 'read',
+        'contextlevel' => CONTEXT_COURSE,
+        'legacy' => array(
+            'teacher' => CAP_ALLOW,
+            'editingteacher' => CAP_ALLOW,
+            'student' => CAP_ALLOW
+        )
     )
 );
 ?>
diff -Naurw moodle-clean/moodle/calendar/lib.php moodle-dev/calendar/lib.php
--- moodle-clean/moodle/calendar/lib.php	2009-05-13 14:08:24.000000000 +0100
+++ moodle-dev/calendar/lib.php	2009-05-13 14:09:35.000000000 +0100
@@ -1429,11 +1429,23 @@
     }
     else {
         $courses = get_my_courses($USER->id, null, null, false);
+        $courses=array_filter($courses,"hidecourse");
     }
 
     return $courses;
 }
 
+function hidecourse($course){
+
+    $context_course = get_context_instance(CONTEXT_COURSE,$course->id);
+    //decide whether they need to see obs on calendar
+    if(has_capability('moodle/calendar:view', $context_course)){
+        return true;
+    }else{
+        return false;
+    }
+}
+
 function calendar_preferences_button() {
     global $CFG, $USER;
 
diff -Naur moodle-clean/moodle/lang/en_utf8/role.php moodle-dev/lang/en_utf8/role.php
--- moodle-clean/moodle/lang/en_utf8/role.php	2009-05-13 12:02:11.000000000 +0100
+++ moodle-dev/lang/en_utf8/role.php	2009-05-12 15:23:12.000000000 +0100
@@ -19,6 +19,7 @@
 $string['calendar:manageentries'] = 'Manage any calendar entries';
 $string['calendar:managegroupentries'] = 'Manage group calendar entries';
 $string['calendar:manageownentries'] = 'Manage own calendar entries';
+$string['calendar:view'] = 'View calendar entries';
 $string['capabilities'] = 'Capabilities';
 $string['capability'] = 'Capability';
 $string['category:create'] = 'Create categories';