xdark

This simple and elegant plugin adds callendar functionality to posts. As soon as you install and activate you can find a “Event Date Select” box in post add/edit section. Choose a date for your event and it will be displayed wherever you place pugins widget. When an event is over it won’t apear anymore.
Works great with custom themes or other calendar plugins.
Features:
<ul>
<li>WordPress built in javascript date picker</li>
<li>Change thumbnail size</li>
<li>Change color, size, type of the text to displayed on the fly through the widget options</li>
<li>Layout fully customizable through a provided css stylesheet (although id’s and classes are provided, you’ll need some css skills here)</li>
</ul>

Posts To Events

This is a simple plugin for adding callendar functionality to posts.

swedish boy

Adds a ‘calendar-box’ to the edit post mode. Here you set up to 10 different dates for your post to be associated with. Through a sidebar widget you control how to display posts that have upcoming dates set to them. This plugin should work fine with other post plugins and the posts you add “calendar-post-dates” will still be displayed in your normal blog post flow.
Features:
<ul>
<li>Adds Date Picker (jQuery) box to ‘edit post mode’.</li>
<li>Up to 10 different dates can be set for one post.</li>
<li>Configurable widget to choose how your sidebar calendar will look.</li>
<li>CSS customizable through your themes stylesheet. Developers can style the output as they like. (Non developers can pick some css-code in the FAQ’s)</li>
</ul>

Calendar Posts

A powerful yet simple plugin for adding calendar functionality to posts. Great for using posts as events and calendar inputs.

Posts To Events vs Calendar Posts