Index: wp-includes/default-widgets.php
===================================================================
--- wp-includes/default-widgets.php	(revision 17287)
+++ wp-includes/default-widgets.php	(working copy)
@@ -327,37 +327,76 @@
 class WP_Widget_Calendar extends WP_Widget {
 
 	function WP_Widget_Calendar() {
-		$widget_ops = array('classname' => 'widget_calendar', 'description' => __( 'A calendar of your site’s posts') );
-		$this->WP_Widget('calendar', __('Calendar'), $widget_ops);
+		$widget_ops = array( 'classname' => 'widget_calendar', 'description' => __( 'A calendar of your site’s posts' ) );
+		$this->WP_Widget( 'calendar', __( 'Calendar' ), $widget_ops );
 	}
 
 	function widget( $args, $instance ) {
-		extract($args);
-		$title = apply_filters('widget_title', empty($instance['title']) ? ' ' : $instance['title'], $instance, $this->id_base);
+		extract( $args );
+
+		$title              = apply_filters( 'widget_title', empty( $instance['title'] ) ? ' ' : $instance['title'], $instance, $this->id_base );
+		$instance_post_type = $this->_get_instance_post_type( $instance );
+
 		echo $before_widget;
+
 		if ( $title )
-			echo $before_title . $title . $after_title;
-		echo '<div id="calendar_wrap">';
-		get_calendar();
-		echo '</div>';
+			echo $before_title . $title . $after_title; ?>
+
+		<div id="calendar_wrap">
+
+			<?php get_calendar( true, true, $instance_post_type ); ?>
+
+		</div>
+
+		<?php
+
 		echo $after_widget;
 	}
 
 	function update( $new_instance, $old_instance ) {
-		$instance = $old_instance;
-		$instance['title'] = strip_tags($new_instance['title']);
+		$instance              = $old_instance;
+		$instance['title']     = strip_tags( $new_instance['title'] );
+		$instance['post_type'] = stripslashes( $new_instance['post_type'] );
 
 		return $instance;
 	}
 
 	function form( $instance ) {
-		$instance = wp_parse_args( (array) $instance, array( 'title' => '' ) );
-		$title = strip_tags($instance['title']);
-?>
-		<p><label for="<?php echo $this->get_field_id('title'); ?>"><?php _e('Title:'); ?></label>
-		<input class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" type="text" value="<?php echo esc_attr($title); ?>" /></p>
-<?php
+		$instance           = wp_parse_args( (array) $instance, array( 'title' => '' ) );
+		$title              = strip_tags( $instance['title'] );
+		$instance_post_type = $this->_get_instance_post_type( $instance );
+		?>
+
+		<p>
+			<label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e( 'Title:' ); ?></label>
+			<input class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" type="text" value="<?php echo esc_attr( $title ); ?>" />
+		</p>
+
+		<p>
+			<label for="<?php echo $this->get_field_id( 'post_type' ); ?>"><?php _e( 'Post Type:' ); ?></label>
+			<select class="widefat" id="<?php echo $this->get_field_id( 'post_type' ); ?>" name="<?php echo $this->get_field_name('post_type'); ?>">
+
+				<?php foreach ( get_post_types( array(), 'objects' ) as $post_type ) :
+					if ( !post_type_supports( $post_type->name, 'calendar' ) )
+						continue;
+					?>
+
+					<option value="<?php echo esc_attr( $post_type->name ); ?>"<?php selected( $post_type->name, $instance_post_type ); ?>><?php echo $post_type->label; ?></option>
+
+				<?php endforeach; ?>
+
+			</select>
+		</p>
+
+		<?php
 	}
+
+	function _get_instance_post_type( $instance ) {
+		if ( !empty( $instance['post_type'] ) && post_type_exists( $instance['post_type'] ) && post_type_supports( $instance['post_type'], 'calendar' ) )
+			return $instance['post_type'];
+
+		return 'post';
+	}
 }
 
 /**
Index: wp-includes/general-template.php
===================================================================
--- wp-includes/general-template.php	(revision 17287)
+++ wp-includes/general-template.php	(working copy)
@@ -1071,10 +1071,16 @@
  *
  * @param bool $initial Optional, default is true. Use initial calendar names.
  * @param bool $echo Optional, default is true. Set to false for return.
+ * @param string $post_type Optional, default is 'post'. Use to get a calendar
+ *                           of a custom post type
  */
-function get_calendar($initial = true, $echo = true) {
+function get_calendar( $initial = true, $echo = true, $post_type = 'post' ) {
 	global $wpdb, $m, $monthnum, $year, $wp_locale, $posts;
 
+	// Check if the post type exists
+	if ( empty( $post_type ) || !post_type_exists( $post_type ) || !post_type_supports( $post_type, 'calendar' ) )
+		return false;
+
 	$cache = array();
 	$key = md5( $m . $monthnum . $year );
 	if ( $cache = wp_cache_get( 'get_calendar', 'calendar' ) ) {
@@ -1088,78 +1094,91 @@
 		}
 	}
 
-	if ( !is_array($cache) )
+	if ( !is_array( $cache ) )
 		$cache = array();
 
 	// Quick check. If we have no posts at all, abort!
 	if ( !$posts ) {
-		$gotsome = $wpdb->get_var("SELECT 1 as test FROM $wpdb->posts WHERE post_type = 'post' AND post_status = 'publish' LIMIT 1");
+		$gotsome = $wpdb->get_var( $wpdb->prepare( "SELECT 1 as test FROM $wpdb->posts WHERE post_type = %s AND post_status = 'publish' LIMIT 1", $post_type ) );
 		if ( !$gotsome ) {
-			$cache[ $key ] = '';
+			$cache[$key] = '';
 			wp_cache_set( 'get_calendar', $cache, 'calendar' );
 			return;
 		}
 	}
 
-	if ( isset($_GET['w']) )
-		$w = ''.intval($_GET['w']);
+	if ( isset( $_GET['w'] ) )
+		$w = ''.intval( $_GET['w'] );
 
 	// week_begins = 0 stands for Sunday
-	$week_begins = intval(get_option('start_of_week'));
+	$week_begins = intval( get_option( 'start_of_week' ) );
 
 	// Let's figure out when we are
-	if ( !empty($monthnum) && !empty($year) ) {
-		$thismonth = ''.zeroise(intval($monthnum), 2);
-		$thisyear = ''.intval($year);
-	} elseif ( !empty($w) ) {
+	if ( !empty( $monthnum ) && !empty( $year ) ) {
+		$thismonth = (string) zeroise( intval( $monthnum ), 2 );
+		$thisyear  = (string) intval( $year );
+	} elseif ( !empty( $w ) ) {
 		// We need to get the month from MySQL
-		$thisyear = ''.intval(substr($m, 0, 4));
-		$d = (($w - 1) * 7) + 6; //it seems MySQL's weeks disagree with PHP's
-		$thismonth = $wpdb->get_var("SELECT DATE_FORMAT((DATE_ADD('{$thisyear}0101', INTERVAL $d DAY) ), '%m')");
-	} elseif ( !empty($m) ) {
-		$thisyear = ''.intval(substr($m, 0, 4));
-		if ( strlen($m) < 6 )
-				$thismonth = '01';
+		$thisyear = (string) intval( substr( $m, 0, 4 ) );
+		$d = ( ( $w - 1 ) * 7 ) + 6; //it seems MySQL's weeks disagree with PHP's
+		$thismonth = $wpdb->get_var( $wpdb->prepare( "SELECT DATE_FORMAT((DATE_ADD(%s, INTERVAL $d DAY) ), '%m')", $thisyear . '0101' ) );
+	} elseif ( !empty( $m ) ) {
+		$thisyear = (string) intval( substr( $m, 0, 4 ) );
+		if ( strlen( $m ) < 6 )
+			$thismonth = '01';
 		else
-				$thismonth = ''.zeroise(intval(substr($m, 4, 2)), 2);
+			$thismonth = (string) zeroise( intval( substr( $m, 4, 2 ) ), 2 );
 	} else {
-		$thisyear = gmdate('Y', current_time('timestamp'));
-		$thismonth = gmdate('m', current_time('timestamp'));
+		$thisyear  = gmdate( 'Y', current_time( 'timestamp' ) );
+		$thismonth = gmdate( 'm', current_time( 'timestamp' ) );
 	}
 
-	$unixmonth = mktime(0, 0 , 0, $thismonth, 1, $thisyear);
-	$last_day = date('t', $unixmonth);
+	$unixmonth = mktime( 0, 0 , 0, $thismonth, 1, $thisyear );
+	$last_day  = date( 't', $unixmonth );
 
 	// Get the next and previous month and year with at least one post
-	$previous = $wpdb->get_row("SELECT MONTH(post_date) AS month, YEAR(post_date) AS year
-		FROM $wpdb->posts
-		WHERE post_date < '$thisyear-$thismonth-01'
-		AND post_type = 'post' AND post_status = 'publish'
-			ORDER BY post_date DESC
-			LIMIT 1");
-	$next = $wpdb->get_row("SELECT MONTH(post_date) AS month, YEAR(post_date) AS year
-		FROM $wpdb->posts
-		WHERE post_date > '$thisyear-$thismonth-{$last_day} 23:59:59'
-		AND post_type = 'post' AND post_status = 'publish'
-			ORDER BY post_date ASC
-			LIMIT 1");
+	$previous = $wpdb->get_row(
+		$wpdb->prepare(
+			"SELECT MONTH(post_date) AS month, YEAR(post_date) AS year
+				FROM $wpdb->posts
+				WHERE post_date < %s
+				AND post_type = %s AND post_status = 'publish'
+				ORDER BY post_date DESC
+				LIMIT 1",
+			$thisyear . '-' . $thismonth . '-01',
+			$post_type
+		)
+	);
 
+	$next = $wpdb->get_row(
+		$wpdb->prepare(
+			"SELECT MONTH(post_date) AS month, YEAR(post_date) AS year
+				FROM $wpdb->posts
+				WHERE post_date > %s
+				AND post_type = %s AND post_status = 'publish'
+				ORDER BY post_date ASC
+				LIMIT 1",
+			$thisyear . '-' . $thismonth . '-' . $last_day . ' 23:59:59',
+			$post_type
+		)
+	);
+
 	/* translators: Calendar caption: 1: month name, 2: 4-digit year */
-	$calendar_caption = _x('%1$s %2$s', 'calendar caption');
-	$calendar_output = '<table id="wp-calendar" summary="' . esc_attr__('Calendar') . '">
-	<caption>' . sprintf($calendar_caption, $wp_locale->get_month($thismonth), date('Y', $unixmonth)) . '</caption>
+	$calendar_caption = _x( '%1$s %2$s', 'calendar caption' );
+	$calendar_output  = '<table id="wp-calendar" summary="' . esc_attr__( 'Calendar' ) . '">
+	<caption>' . sprintf( $calendar_caption, $wp_locale->get_month( $thismonth ), date( 'Y', $unixmonth ) ) . '</caption>
 	<thead>
 	<tr>';
 
 	$myweek = array();
 
-	for ( $wdcount=0; $wdcount<=6; $wdcount++ ) {
-		$myweek[] = $wp_locale->get_weekday(($wdcount+$week_begins)%7);
+	for ( $wdcount=0; $wdcount <= 6; $wdcount++ ) {
+		$myweek[] = $wp_locale->get_weekday( ( $wdcount + $week_begins ) % 7 );
 	}
 
 	foreach ( $myweek as $wd ) {
-		$day_name = (true == $initial) ? $wp_locale->get_weekday_initial($wd) : $wp_locale->get_weekday_abbrev($wd);
-		$wd = esc_attr($wd);
+		$day_name         = ( true == $initial ) ? $wp_locale->get_weekday_initial( $wd ) : $wp_locale->get_weekday_abbrev( $wd );
+		$wd               = esc_attr( $wd );
 		$calendar_output .= "\n\t\t<th scope=\"col\" title=\"$wd\">$day_name</th>";
 	}
 
@@ -1170,19 +1189,17 @@
 	<tfoot>
 	<tr>';
 
-	if ( $previous ) {
-		$calendar_output .= "\n\t\t".'<td colspan="3" id="prev"><a href="' . get_month_link($previous->year, $previous->month) . '" title="' . esc_attr( sprintf(__('View posts for %1$s %2$s'), $wp_locale->get_month($previous->month), date('Y', mktime(0, 0 , 0, $previous->month, 1, $previous->year)))) . '">&laquo; ' . $wp_locale->get_month_abbrev($wp_locale->get_month($previous->month)) . '</a></td>';
-	} else {
-		$calendar_output .= "\n\t\t".'<td colspan="3" id="prev" class="pad">&nbsp;</td>';
-	}
+	if ( $previous )
+		$calendar_output .= "\n\t\t" . '<td colspan="3" id="prev"><a href="' . get_month_link( $previous->year, $previous->month ) . '" title="' . esc_attr( sprintf(__( 'View posts for %1$s %2$s' ), $wp_locale->get_month( $previous->month ), date( 'Y', mktime( 0, 0 , 0, $previous->month, 1, $previous->year ) ) ) ) . '">&laquo; ' . $wp_locale->get_month_abbrev( $wp_locale->get_month( $previous->month ) ) . '</a></td>';
+	else
+		$calendar_output .= "\n\t\t" . '<td colspan="3" id="prev" class="pad">&nbsp;</td>';
 
-	$calendar_output .= "\n\t\t".'<td class="pad">&nbsp;</td>';
+	$calendar_output .= "\n\t\t" . '<td class="pad">&nbsp;</td>';
 
-	if ( $next ) {
-		$calendar_output .= "\n\t\t".'<td colspan="3" id="next"><a href="' . get_month_link($next->year, $next->month) . '" title="' . esc_attr( sprintf(__('View posts for %1$s %2$s'), $wp_locale->get_month($next->month), date('Y', mktime(0, 0 , 0, $next->month, 1, $next->year))) ) . '">' . $wp_locale->get_month_abbrev($wp_locale->get_month($next->month)) . ' &raquo;</a></td>';
-	} else {
-		$calendar_output .= "\n\t\t".'<td colspan="3" id="next" class="pad">&nbsp;</td>';
-	}
+	if ( $next )
+		$calendar_output .= "\n\t\t" . '<td colspan="3" id="next"><a href="' . get_month_link( $next->year, $next->month ) . '" title="' . esc_attr( sprintf( __( 'View posts for %1$s %2$s' ), $wp_locale->get_month( $next->month ), date( 'Y', mktime( 0, 0 , 0, $next->month, 1, $next->year ) ) ) ) . '">' . $wp_locale->get_month_abbrev( $wp_locale->get_month( $next->month ) ) . ' &raquo;</a></td>';
+	else
+		$calendar_output .= "\n\t\t" . '<td colspan="3" id="next" class="pad">&nbsp;</td>';
 
 	$calendar_output .= '
 	</tr>
@@ -1192,10 +1209,18 @@
 	<tr>';
 
 	// Get days with posts
-	$dayswithposts = $wpdb->get_results("SELECT DISTINCT DAYOFMONTH(post_date)
-		FROM $wpdb->posts WHERE post_date >= '{$thisyear}-{$thismonth}-01 00:00:00'
-		AND post_type = 'post' AND post_status = 'publish'
-		AND post_date <= '{$thisyear}-{$thismonth}-{$last_day} 23:59:59'", ARRAY_N);
+	$dayswithposts = $wpdb->get_results(
+		$wpdb->prepare(
+			"SELECT DISTINCT DAYOFMONTH(post_date)
+				FROM $wpdb->posts WHERE post_date >= %s
+				AND post_type = %s AND post_status = 'publish'
+				AND post_date <= %s",
+			$thisyear . '-' . $thismonth . '-01 00:00:00',
+			$post_type,
+			$thisyear . '-' . $thismonth . '-' . $last_day . ' 23:59:59'
+		),
+		ARRAY_N
+	);
 	if ( $dayswithposts ) {
 		foreach ( (array) $dayswithposts as $daywith ) {
 			$daywithpost[] = $daywith[0];
@@ -1204,26 +1229,32 @@
 		$daywithpost = array();
 	}
 
-	if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== false || stripos($_SERVER['HTTP_USER_AGENT'], 'camino') !== false || stripos($_SERVER['HTTP_USER_AGENT'], 'safari') !== false)
+	if ( strpos( $_SERVER['HTTP_USER_AGENT'], 'MSIE' ) !== false || stripos( $_SERVER['HTTP_USER_AGENT'], 'camino' ) !== false || stripos( $_SERVER['HTTP_USER_AGENT'], 'safari' ) !== false )
 		$ak_title_separator = "\n";
 	else
 		$ak_title_separator = ', ';
 
 	$ak_titles_for_day = array();
-	$ak_post_titles = $wpdb->get_results("SELECT ID, post_title, DAYOFMONTH(post_date) as dom "
-		."FROM $wpdb->posts "
-		."WHERE post_date >= '{$thisyear}-{$thismonth}-01 00:00:00' "
-		."AND post_date <= '{$thisyear}-{$thismonth}-{$last_day} 23:59:59' "
-		."AND post_type = 'post' AND post_status = 'publish'"
+	$ak_post_titles    = $wpdb->get_results(
+		$wpdb->prepare(
+			"SELECT ID, post_title, DAYOFMONTH(post_date) as dom
+				FROM $wpdb->posts
+				WHERE post_date >= %s
+				AND post_date <= %s
+				AND post_type = %s AND post_status = 'publish'",
+			$thisyear . '-' . $thismonth . '-01 00:00:00',
+			$thisyear . '-' . $thismonth . '-' . $last_day . ' 23:59:59',
+			$post_type
+		)
 	);
 	if ( $ak_post_titles ) {
 		foreach ( (array) $ak_post_titles as $ak_post_title ) {
 
 				$post_title = esc_attr( apply_filters( 'the_title', $ak_post_title->post_title, $ak_post_title->ID ) );
 
-				if ( empty($ak_titles_for_day['day_'.$ak_post_title->dom]) )
+				if ( empty( $ak_titles_for_day['day_'.$ak_post_title->dom] ) )
 					$ak_titles_for_day['day_'.$ak_post_title->dom] = '';
-				if ( empty($ak_titles_for_day["$ak_post_title->dom"]) ) // first one
+				if ( empty( $ak_titles_for_day["$ak_post_title->dom"] ) ) // first one
 					$ak_titles_for_day["$ak_post_title->dom"] = $post_title;
 				else
 					$ak_titles_for_day["$ak_post_title->dom"] .= $ak_title_separator . $post_title;
@@ -1232,44 +1263,44 @@
 
 
 	// See how much we should pad in the beginning
-	$pad = calendar_week_mod(date('w', $unixmonth)-$week_begins);
+	$pad = calendar_week_mod( date( 'w', $unixmonth ) - $week_begins );
 	if ( 0 != $pad )
-		$calendar_output .= "\n\t\t".'<td colspan="'. esc_attr($pad) .'" class="pad">&nbsp;</td>';
+		$calendar_output .= "\n\t\t".'<td colspan="'. esc_attr( $pad ) .'" class="pad">&nbsp;</td>';
 
-	$daysinmonth = intval(date('t', $unixmonth));
+	$daysinmonth = intval( date( 't', $unixmonth ) );
 	for ( $day = 1; $day <= $daysinmonth; ++$day ) {
-		if ( isset($newrow) && $newrow )
+		if ( isset( $newrow ) && $newrow )
 			$calendar_output .= "\n\t</tr>\n\t<tr>\n\t\t";
 		$newrow = false;
 
-		if ( $day == gmdate('j', current_time('timestamp')) && $thismonth == gmdate('m', current_time('timestamp')) && $thisyear == gmdate('Y', current_time('timestamp')) )
+		if ( $day == gmdate( 'j', current_time( 'timestamp' ) ) && $thismonth == gmdate( 'm', current_time( 'timestamp' ) ) && $thisyear == gmdate( 'Y', current_time( 'timestamp' ) ) )
 			$calendar_output .= '<td id="today">';
 		else
 			$calendar_output .= '<td>';
 
-		if ( in_array($day, $daywithpost) ) // any posts today?
-				$calendar_output .= '<a href="' . get_day_link($thisyear, $thismonth, $day) . "\" title=\"" . esc_attr($ak_titles_for_day[$day]) . "\">$day</a>";
+		if ( in_array( $day, $daywithpost ) ) // any posts today?
+				$calendar_output .= '<a href="' . get_day_link( $thisyear, $thismonth, $day ) . "\" title=\"" . esc_attr( $ak_titles_for_day[$day] ) . "\">$day</a>";
 		else
 			$calendar_output .= $day;
 		$calendar_output .= '</td>';
 
-		if ( 6 == calendar_week_mod(date('w', mktime(0, 0 , 0, $thismonth, $day, $thisyear))-$week_begins) )
+		if ( 6 == calendar_week_mod( date( 'w', mktime( 0, 0 , 0, $thismonth, $day, $thisyear ) ) - $week_begins ) )
 			$newrow = true;
 	}
 
-	$pad = 7 - calendar_week_mod(date('w', mktime(0, 0 , 0, $thismonth, $day, $thisyear))-$week_begins);
+	$pad = 7 - calendar_week_mod( date( 'w', mktime( 0, 0 , 0, $thismonth, $day, $thisyear ) ) - $week_begins );
 	if ( $pad != 0 && $pad != 7 )
-		$calendar_output .= "\n\t\t".'<td class="pad" colspan="'. esc_attr($pad) .'">&nbsp;</td>';
+		$calendar_output .= "\n\t\t".'<td class="pad" colspan="' . esc_attr( $pad ) . '">&nbsp;</td>';
 
 	$calendar_output .= "\n\t</tr>\n\t</tbody>\n\t</table>";
 
-	$cache[ $key ] = $calendar_output;
+	$cache[$key] = $calendar_output;
 	wp_cache_set( 'get_calendar', $cache, 'calendar' );
 
 	if ( $echo )
-		echo apply_filters( 'get_calendar',  $calendar_output );
+		echo apply_filters( 'get_calendar', $calendar_output );
 	else
-		return apply_filters( 'get_calendar',  $calendar_output );
+		return apply_filters( 'get_calendar', $calendar_output );
 
 }
 
Index: wp-includes/post.php
===================================================================
--- wp-includes/post.php	(revision 17287)
+++ wp-includes/post.php	(working copy)
@@ -26,7 +26,7 @@
 		'hierarchical' => false,
 		'rewrite' => false,
 		'query_var' => false,
-		'supports' => array( 'title', 'editor', 'author', 'thumbnail', 'excerpt', 'trackbacks', 'custom-fields', 'comments', 'revisions', 'post-formats' ),
+		'supports' => array( 'title', 'editor', 'author', 'thumbnail', 'excerpt', 'trackbacks', 'custom-fields', 'comments', 'revisions', 'post-formats', 'calendar' ),
 	) );
 
 	register_post_type( 'page', array(
@@ -1209,9 +1209,10 @@
  *
  * All features are directly associated with a functional area of the edit screen, such as the
  * editor or a meta box: 'title', 'editor', 'comments', 'revisions', 'trackbacks', 'author',
- * 'excerpt', 'page-attributes', 'thumbnail', and 'custom-fields'.
+ * 'excerpt', 'page-attributes', 'thumbnail', 'calendar' and 'custom-fields'.
  *
  * Additionally, the 'revisions' feature dictates whether the post type will store revisions,
+ * the 'calendar' feature will show the post type in the select box in the calendar widget,
  * and the 'comments' feature dicates whether the comments count will show on the edit screen.
  *
  * @since 3.0.0