diff --git a/calendar/resources/content/calendar.js b/calendar/resources/content/calendar.js
index dd34d9524e2e..98fb24bfe2f8 100644
--- a/calendar/resources/content/calendar.js
+++ b/calendar/resources/content/calendar.js
@@ -131,6 +131,50 @@ function calendarInit()
 
    document.getElementById("view-deck")
            .addEventListener("dayselect", observeViewDaySelect, false);
+
+   // Handle commandline args
+   for (var i=0; i < window.arguments.length; i++) {
+       try {
+           var cl = window.arguments[i].QueryInterface(Components.interfaces.nsICommandLine);
+       } catch(ex) {
+           dump("unknown argument passed to main window\n");
+           continue;
+       }
+       handleCommandLine(cl);
+   }
+}
+
+function handleCommandLine(aComLine) {
+    var calurl;
+    try {
+        calurl = aComLine.handleFlagWithParam("subscribe", false);
+    } catch(ex) {}
+    if (calurl) {
+        var uri = makeURL(calurl);
+        var cal = getCalendarManager().createCalendar('ics', uri);
+        getCalendarManager().registerCalendar(cal);
+
+        // Strip ".ics" from filename for use as calendar name, taken from 
+        // calendarCreation.js
+        var fullPathRegex = new RegExp("([^/:]+)[.]ics$");
+        var prettyName = calurl.match(fullPathRegex);
+        var name;
+
+        if (prettyName && prettyName.length >= 1) {
+            name = decodeURIComponent(prettyName[1]);
+        } else {
+            name = calGetString("calendar", "untitledCalendarName");
+        }
+        cal.name = name;
+    }
+
+    var date;
+    try {
+        date = aComLine.handleFlagWithParam("showdate", false);
+    } catch(ex) {}
+    if (date) {
+        currentView().goToDay(jsDateToDateTime(new Date(date)));
+    }
 }
 
 /* Called at midnight to tell us to update the views and other ui bits */
diff --git a/calendar/resources/content/calendarService.js b/calendar/resources/content/calendarService.js
index 4c1d74122c53..41c3ef3cf1d1 100644
--- a/calendar/resources/content/calendarService.js
+++ b/calendar/resources/content/calendarService.js
@@ -123,16 +123,18 @@ CLineService.prototype = {
     /* nsICommandLineHandler */
 
     handle : function service_handle(cmdLine) {
-        if (cmdLine.handleFlag("calendar", false)) {
-            wwatch = Components.classes[WINDOWWATCHER_CONTRACTID]
-                               .getService(nsIWindowWatcher);
-            wwatch.openWindow(null, "chrome://calendar/content/",
+        // just pass all arguments on to the Sunbird window
+        wwatch = Components.classes[WINDOWWATCHER_CONTRACTID]
+                           .getService(nsIWindowWatcher);
+        wwatch.openWindow(null, "chrome://calendar/content/",
                               "_blank", "chrome,dialog=no,all", cmdLine);
-            cmdLine.preventDefault = true;
-        }
+        cmdLine.preventDefault = true;
     },
 
-    helpInfo : "  -calendar            Start with the calendar.\n"
+    helpInfo : "  -subscribe           Pass in a path pointing to a calendar\n" +
+               "                       to subscribe to.\n" +
+               "  -showdate            Pass in a value for a javascript date\n" +
+               "                       to show this date on startup.\n"
 };
 
 /* factory for command line handler service (CLineService) */