diff --git a/gen/calendar.py b/gen/calendar.py
index 348060e..08c1e50 100644
--- a/gen/calendar.py
+++ b/gen/calendar.py
@@ -17,7 +17,8 @@ class Calendar(Type):
                  specificWritePermission=False, width=None, height=300,
                  colspan=1, master=None, masterValue=None, focus=False,
                  mapping=None, label=None, maxEventLength=50,
-                 otherCalendars=None):
+                 otherCalendars=None, startDate=None, endDate=None,
+                 defaultDate=None):
         Type.__init__(self, validator, (0,1), None, default, False, False,
                       show, page, group, layouts, move, False, False,
                       specificReadPermission, specificWritePermission,
@@ -51,6 +52,19 @@ class Calendar(Type):
         #   leading "#" when relevant) into which events of the calendar must
         #   appear.
         self.otherCalendars = otherCalendars
+        # One may limit event encoding and viewing to a limited period of time,
+        # via p_startDate and p_endDate. Those parameters, if given, must hold
+        # methods accepting no arg and returning a Zope DateTime instance.
+        self.startDate = startDate
+        # Beware: specify an end date with an hour like
+        # DateTime('2012/10/13 23:59:59') to avoid surprises.
+        self.endDate = endDate
+        # If a default date is specified, it must be a method accepting no arg
+        # and returning a DateTime instance. As soon as the calendar is shown,
+        # the month where this date is included will be shown. If not default
+        # date is specified, it will be 'now' at the moment the calendar is
+        # shown.
+        self.defaultDate = defaultDate
 
     def getSiblingMonth(self, month, prevNext):
         '''Gets the next or previous month (depending of p_prevNext) relative
@@ -171,6 +185,22 @@ class Calendar(Type):
         else:
             return obj.translate('%s_event_%s' % (self.labelId, eventType))
 
+    def getStartDate(self, obj):
+        '''Get the start date for this calendar if defined.'''
+        if self.startDate: return self.startDate(obj.appy())
+
+    def getEndDate(self, obj):
+        '''Get the end date for this calendar if defined.'''
+        if self.endDate: return self.endDate(obj.appy())
+
+    def getDefaultDate(self, obj):
+        '''Get the default date that must appear as soon as the calendar is
+           shown.'''
+        if self.defaultDate:
+            return self.defaultDate(obj.appy())
+        else:
+            return DateTime() # Now
+
     def createEvent(self, obj, date, handleEventSpan=True):
         '''Create a new event in the calendar, at some p_date (day). If
            p_handleEventSpan is True, we will use rq["eventSpan"] and also
diff --git a/gen/ui/widgets/calendar.pt b/gen/ui/widgets/calendar.pt
index 2138803..4935bf2 100644
--- a/gen/ui/widgets/calendar.pt
+++ b/gen/ui/widgets/calendar.pt
@@ -5,13 +5,16 @@
                  month request/month;
                  monthDayOne python: DateTime('%s/01' % month);
                  today python: DateTime('00:00');
-                 todayMonth python: today.strftime('%Y/%m');
+                 defaultDate python: contextObj.callField(fieldName, 'getDefaultDate', contextObj);
+                 defaultDateMonth python: defaultDate.strftime('%Y/%m');
                  grid python: contextObj.callField(fieldName, 'getMonthGrid', month);
                  previousMonth python: contextObj.callField(fieldName, 'getSiblingMonth', month, 'previous');
                  nextMonth python: contextObj.callField(fieldName, 'getSiblingMonth', month, 'next');
                  widget python: contextObj.getAppyType(fieldName, asDict=True);
                  mayEdit python: contextObj.allows(widget['writePermission']);
                  objUrl contextObj/absolute_url;
+                 startDate python: contextObj.callField(fieldName, 'getStartDate', contextObj);
+                 endDate python: contextObj.callField(fieldName, 'getEndDate', contextObj);
                  otherCalendars python: contextObj.callField(fieldName, 'getOtherCalendars', contextObj);"
      tal:attributes="id ajaxHookId">
 
@@ -19,15 +22,25 @@
         tal:content="python: 'var %s_maxEventLength = %d;' % (fieldName, widget['maxEventLength'])">
 </script>
 <tal:comment replace="nothing">Month chooser</tal:comment>
-<div style="margin-bottom: 5px">
- <img style="cursor:pointer"
+<div style="margin-bottom: 5px"
+     tal:define="fmt python: '%Y/%m/%d';
+                 goBack python: not startDate or (startDate.strftime(fmt) &lt; grid[0][0].strftime(fmt));
+                 goForward python: not endDate or (endDate.strftime(fmt) &gt; grid[-1][-1].strftime(fmt))">
+ <tal:comment replace="nothing">Go to the previous month</tal:comment>
+ <img style="cursor:pointer" tal:condition="goBack"
       tal:attributes="src string: $appUrl/ui/arrowLeftSimple.png;
                       onclick python: 'askMonthView(\'%s\',\'%s\',\'%s\',\'%s\')' % (ajaxHookId,objUrl,fieldName,previousMonth)"/>
- <input type="button"
-        tal:attributes="value python: _('today');
-                        onclick python: 'askMonthView(\'%s\',\'%s\',\'%s\',\'%s\')' % (ajaxHookId,objUrl,fieldName,todayMonth);
-                        disabled monthDayOne/isCurrentMonth"/>
- <img style="cursor:pointer"
+ <tal:comment replace="nothing">Go back to the default date</tal:comment>
+ <tal:button condition="python: goBack or goForward">
+  <input type="button"
+         tal:define="fmt python: '%Y/%m';
+                     label python: test(defaultDate.strftime(fmt) == today.strftime(fmt), 'today', 'goto_source')"
+         tal:attributes="value python: _(label);
+                         onclick python: 'askMonthView(\'%s\',\'%s\',\'%s\',\'%s\')' % (ajaxHookId,objUrl,fieldName,defaultDateMonth);
+                         disabled python: defaultDate.strftime(fmt) == monthDayOne.strftime(fmt)"/>
+ </tal:button>
+ <tal:comment replace="nothing">Go to the next month</tal:comment>
+ <img style="cursor:pointer" tal:condition="goForward"
       tal:attributes="src string: $appUrl/ui/arrowRightSimple.png;
                       onclick python: 'askMonthView(\'%s\',\'%s\',\'%s\',\'%s\')' % (ajaxHookId,objUrl,fieldName,nextMonth)"/>
  <span tal:content="python: _('month_%s' % monthDayOne.aMonth())"></span>
@@ -46,44 +59,55 @@
   <tal:comment replace="nothing">The calendar in itself</tal:comment>
   <tr tal:repeat="row grid" valign="top" tal:attributes="height rowHeight">
    <tal:cell repeat="date row">
-   <td tal:define="events python: contextObj.callField(fieldName, 'getEventsAt', contextObj, date);
-                   spansDays python: contextObj.callField(fieldName, 'hasEventsAt', contextObj, date+1, events);
-                   mayCreate python: mayEdit and not events;
-                   mayDelete python: mayEdit and events;"
-       tal:attributes="style python: test(date.isCurrentDay(), 'font-weight:bold', 'font-weight:normal');
-                       class python: test(date &lt; today, 'even', 'odd');
-                       onmouseover python: test(mayEdit, 'this.getElementsByTagName(\'img\')[0].style.visibility=\'visible\'', '');
-                       onmouseout python: test(mayEdit, 'this.getElementsByTagName(\'img\')[0].style.visibility=\'hidden\'', '')">
-    <tal:day define="day date/day;
-                     dayString python: date.strftime('%Y/%m/%d')">
-     <span tal:content="day"></span>
-     <span tal:condition="python: day == 1"
-           tal:content="python: _('month_%s_short' % date.aMonth())"></span>
-     <tal:comment replace="nothing">Icon for adding an event</tal:comment>
-     <img tal:condition="mayCreate" style="visibility:hidden; cursor:pointer"
-          tal:attributes="src string: $appUrl/ui/plus.png;
+    <tal:cel define="tooEarly python: startDate and (date &lt; startDate);
+                     tooLate python: endDate and not tooEarly and (date &gt; endDate);
+                     inRange python: not tooEarly and not tooLate">
+     <tal:comment replace="nothing">Dump an empty cell if we are out of the supported date range</tal:comment>
+     <td tal:condition="not: inRange"
+         tal:attributes="class python: test(date &lt; today, 'even', 'odd');">
+     </td>
+     <tal:comment replace="nothing">Dump a normal cell if we are in range</tal:comment>
+     <tal:td condition="inRange">
+     <td tal:define="events python: contextObj.callField(fieldName, 'getEventsAt', contextObj, date);
+                     spansDays python: contextObj.callField(fieldName, 'hasEventsAt', contextObj, date+1, events);
+                     mayCreate python: mayEdit and not events;
+                     mayDelete python: mayEdit and events;"
+         tal:attributes="style python: test(date.isCurrentDay(), 'font-weight:bold', 'font-weight:normal');
+                         class python: test(date &lt; today, 'even', 'odd');
+                         onmouseover python: test(mayEdit, 'this.getElementsByTagName(\'img\')[0].style.visibility=\'visible\'', '');
+                         onmouseout python: test(mayEdit, 'this.getElementsByTagName(\'img\')[0].style.visibility=\'hidden\'', '')">
+      <tal:day define="day date/day;
+                       dayString python: date.strftime('%Y/%m/%d')">
+       <span tal:content="day"></span>
+       <span tal:condition="python: day == 1"
+             tal:content="python: _('month_%s_short' % date.aMonth())"></span>
+       <tal:comment replace="nothing">Icon for adding an event</tal:comment>
+       <img tal:condition="mayCreate" style="visibility:hidden; cursor:pointer"
+            tal:attributes="src string: $appUrl/ui/plus.png;
                           onclick python: 'openEventPopup(\'new\',\'%s\',\'%s\')' % (fieldName, dayString)"/>
-     <tal:comment replace="nothing">Icon for deleting an event</tal:comment>
-     <img tal:condition="mayDelete" style="visibility:hidden; cursor:pointer"
-          tal:attributes="src string: $appUrl/ui/delete.png;
+       <tal:comment replace="nothing">Icon for deleting an event</tal:comment>
+       <img tal:condition="mayDelete" style="visibility:hidden; cursor:pointer"
+            tal:attributes="src string: $appUrl/ui/delete.png;
                           onclick python: 'openEventPopup(\'del\',\'%s\',\'%s\',\'%s\')' % (fieldName, dayString, str(spansDays))"/>
-     <tal:events condition="events">
+       <tal:events condition="events">
        <tal:comment replace="nothing">A single event is allowed for the moment</tal:comment>
        <div tal:define="eventType python: events[0]['eventType']">
         <span style="color: grey"
               tal:content="python: contextObj.callField(fieldName, 'getEventName', contextObj, eventType)"></span>
        </div>
-     </tal:events>
-     <tal:comment replace="nothing">Events from other calendars</tal:comment>
-     <tal:others condition="otherCalendars">
-      <tal:e define="otherEvents python: contextObj.callField(fieldName,'getOtherEventsAt',contextObj,date,otherCalendars)"
-             condition="otherEvents">
-       <div tal:repeat="event otherEvents" tal:content="event/name"
-            tal:attributes="style python: 'color: %s;; font-style: italic' % event['color']"></div>
-      </tal:e>
-     </tal:others>
-    </tal:day>
-   </td>
+       </tal:events>
+       <tal:comment replace="nothing">Events from other calendars</tal:comment>
+       <tal:others condition="otherCalendars">
+        <tal:e define="otherEvents python: contextObj.callField(fieldName,'getOtherEventsAt',contextObj,date,otherCalendars)"
+               condition="otherEvents">
+         <div tal:repeat="event otherEvents" tal:content="event/name"
+              tal:attributes="style python: 'color: %s;; font-style: italic' % event['color']"></div>
+        </tal:e>
+       </tal:others>
+      </tal:day>
+     </td>
+     </tal:td>
+    </tal:cel>
    </tal:cell>
   </tr>
 </table>
@@ -157,9 +181,9 @@
 
 <tal:comment replace="nothing">View macro</tal:comment>
 <metal:view define-macro="view"
-            tal:define="now python: DateTime();
+            tal:define="defaultDate python: contextObj.callField(widget['name'], 'getDefaultDate', contextObj);
                         dummy python: request.set('fieldName', widget['name']);
-                        dummy python: request.set('month', now.strftime('%Y/%m'))">
+                        dummy python: request.set('month', defaultDate.strftime('%Y/%m'))">
  <metal:call use-macro="app/ui/widgets/calendar/macros/viewMonth"/>
 </metal:view>