Easily insert any WordPress sidebar widget into a post or page using a shortcode. http://wp.smashingmagazine.com/2012/12/11/inserting-widgets-with-shortcodes/

widget-shortcode.php

<?php
 
/**
 * Plugin Name: Widget Shortcode
 * Plugin URI: http://wp.smashingmagazine.com/2012/12/11/inserting-widgets-with-shortcodes/
 * Description: Easily insert any WordPress sidebar widget into a post or page using a shortcode.
 * Author: Smashing Magazine
 * Author URI: http://www.smashingmagazine.com
 * Version: 1.0
 */
 
add_shortcode( 'widget', 'my_widget_shortcode' );
 
function my_widget_shortcode( $atts ) {
 
// Configure defaults and extract the attributes into variables
extract( shortcode_atts( 
  array( 
  	'type'   => '',
		'title'  => '',
		'scheme' => 'light'
	), 
	$atts 
));
 
$args = array(
	'before_widget' => '<div class="box widget scheme-' . $scheme . ' ">',
	'after_widget'  => '</div>',
	'before_title'  => '<div class="widget-title">',
	'after_title'   => '</div>',
);
 
ob_start();
the_widget( $type, $atts, $args ); 
$output = ob_get_clean();
 
return $output;