Simple bit of code to register a custom post type. Use as an mu-plugin.

cpt-show.php

<?php
/*
Plugin Name: show Custom Post Type
Plugin URI: http://www.offbroadway.com/
Description: Custom post type for OffBroadway.com
Author: Van Patten Media
Version: 1.0
Author URI: http://www.vanpattenmedia.com/
*/


/**
 *
 * Register post type
 *
 */

if ( !post_type_exists('show') ) {
	function register_show_type() {
		$label_singular = 'Show';
		$label_plural   = 'Shows';

		register_post_type(
			'show',
			array(
				'label'           => $label_plural,
				'description'     => '',
				'public'          => true,
				'show_ui'         => true,
				'show_in_menu'    => true,
				'capability_type' => 'post',
				'hierarchical'    => false,
				'query_var'       => true,
				'has_archive'     => true,
				'rewrite' => array(
					'slug'       => 'show',
					'with_front' => false,
				),
				'supports' => array(
					'title',
					'editor',
					'revisions',
					'thumbnail',
					'custom-fields',
				),
				'labels' => array (
					'name'               => $label_plural,
					'singular_name'      => $label_singular,
					'menu_name'          => $label_plural,
					'add_new'            => 'Add New',
					'add_new_item'       => 'Add New ' . $label_singular,
					'edit'               => 'Edit',
					'edit_item'          => 'Edit ' . $label_singular,
					'new_item'           => 'New ' . $label_singular,
					'view'               => 'View ' . $label_singular,
					'view_item'          => 'View ' . $label_singular,
					'search_items'       => 'Search ' . $label_plural,
					'not_found'          => 'No ' . $label_plural . ' Found',
					'not_found_in_trash' => 'No ' . $label_plural . ' Found in Trash',
					'parent'             => 'Parent ' . $label_singular,
				)
			)
		);
	}
	add_action('init', 'register_show_type');
}