$result = mysql_query("select * from calendar");
$i = 0;
while ($r = mysql_fetch_array($result)){
	$list[$r['year']][$r['month']][$r['day']][$i][]=$r['teacher'];
	$list[$r['year']][$r['month']][$r['day']][$i][]=$r['subject'];	
	$list[$r['year']][$r['month']][$r['day']][$i][]=$r['block'];
	$list[$r['year']][$r['month']][$r['day']][$i][]=$r['description'];
	echo $i++;
}

Array
(
    [2005] => Array
        (
            [1] => Array
                (
                    [15] => Array
                        (
                            [0] => Array
                                (
                                    [0] => teacher
                                    [1] => subject
                                    [2] => a
                                    [3] => description
                                )

                            [3] => Array
                                (
                                    [0] => teacher
                                    [1] => subject
                                    [2] => a
                                    [3] => description
                                )

                        )

                    [12] => Array
                        (
                            [1] => Array
                                (
                                    [0] => teacherasdf
                                    [1] => subjectet3
                                    [2] => a
                                    [3] => descriptionsadf
                                )

                        )

                    [8] => Array
                        (
                            [2] => Array
                                (
                                    [0] => teacherasdfe
                                    [1] => subjectasdf
                                    [2] => a
                                    [3] => description2354wed
                                )

                        )

                )

        )

)