The module Qivva Eventlist Calendar Module for Joomla 1.6 is a nice Ajax calendar that presents events from the component EventList.

There is a bug switching month when SEF rewrite is on and / or the parameter Remember = 1 and / or the module is loaded with Modules Anywhere.  The fix is quick and easy:

File /modules/mod_eventlistcalqajax/mod_eventlistcalqajax.php roughly at line 55 we need to use JApplication::getUserState instead of $mainframe->getUserState.  Change the code as follows:

	if ($Remember == 1) // Remember which month / year is selected. Don't jump back to tday on page change
	{
			/*
			 * Riccardo Zorn: changed $mainframe->  to $JApplication:: (supported); if Remember is enabled we could go here!
			 * */
		jimport( 'joomla.application.application' );// zorn
		
		if ($req_month == 0) 
		{
			$req_month = JApplication::getUserState("eventlistcalqmonth".$module->id); 
			$req_year =  JApplication::getUserState("eventlistcalqyear".$module->id);
		}
		else
		{
			JApplication::setUserState("eventlistcalqmonth".$module->id,$req_month);
			JApplication::setUserState("eventlistcalqyear".$module->id,$req_year);
		}
	}

file /modules/mod_eventlistcalqajax/mod_ajaxloader.php after line 40:

$mainframe->initialise();

/*
 * Riccardo Zorn: added as global, fallback read from the get parameters.
 * */
global $Itemid; 

 if (!isset($Itemid)) {
 $Itemid = JRequest::getInt('Itemid', 0);
 }
/* end of change */

This is it.

(if you are also using Modules Anywhere, make sure the module is published on all pages, otherwise the previous/next month will not work in Ajax mode!)