A new widget that shows a calendar based on existing post types.
<ul>
<li>Select any available post type to show</li>
<li>Filter by any custom taxonomy term tied to the selected post type</li>
<li>List a maximum of 10 items below calendar</li>
<li>Set a prefix for every listed item</li>
<li>Filters and hooks</li>
</ul>

WordPress Calendar For Custom Post Types

Because the builtin calendar doesn't have such an option.

Stanislav Khromov

Content Template Widget (previously View Template Widget) is useful for inserting information boxes about the current post being displayed in the widget area of your theme. It is possible to configure which content types each widget will be shown on.
This plugin requires Toolset Views. Click the link below for more information on this plugin: 
http://wp-types.com/home/views-create-elegant-displays-for-your-content/
Usage
Basic usage
<ul>
<li>Activate Views for WordPress</li>
<li>Create a Content Template</li>
<li>Add a WP Views Content Template widget to your site</li>
</ul>
The title field supports shortcodes, so you can easily use a wpv- shortcode in the widget title.
Although it is possible to expose the widget on all pages by selecting “Show widget everywhere”, it is most useful on predefined post types, as 
archives, listings and tag pages will only return one result. (Most often the first item in the archive.)
To display a listing in the widget area, use a View Widget instead. (Included in Views.)
<h3>Requirements</h3>
<ul>
<li>PHP 5.2 or higher</li>
</ul>
<h3>Translations</h3>
<ul>
<li>None. Translations welcome.</li>
</ul>

Content Template Widget for Toolset Views

Allows you to add a Widget that displays a Content Template from Toolset Views

WordPress Calendar For Custom Post Types vs Content Template Widget for Toolset Views