horvath.agoston

Very simple, highly customizable counter widget for showing difference in 
days from a specified date and time. Allows HTML in title and body. Can 
count up and down. Supports multiple instances.
Originally developed as a baby age counter, but can be used for any counting 
job.
The options in the widget are:
<ul>
<li>
Title is the widget’s title. It can contain HTML; its value is simply embedded into the resulting HTML page.
</li>
<li>
Content is the widget content field. It uses the <a href="http://www.php.net/manual/en/dateinterval.format.php" rel="nofollow ugc">DateInterval::format</a> 
function to format the field contents. You can use any field specifiers from 
that function. Its contents are also embedded into the resulting HTML page, 
so over the %-tags, you are free to use any HTML you want.
</li>
<li>
Date specifies the date we should count difference from. Since this 
plugin simply calculates the difference between ‘now’ and the specified date 
(in 24-hour days), it can be used for counting down, for dates in the 
future, or counting up, for dates in the past.
</li>
</ul>
You can have multiple instances of this widget, of course.
For an example usage, see the screenshots section.

Count All

Very simple, highly customizable counter widget for showing difference in days from a specified date and time.

Michael Henke

This plugin will display a count down in days until a certain date. 
This date can be set in the wordpress administration panel as well as the text related to it.
For example:
<ul>
<li>Our wedding will be in 14 days.</li>
<li>31 days until final exams.</li>
<li>In 2 days Apple will release its iPad…</li>
</ul>
The plugin can be used in a widgetized sidebar or in your theme.
On the configuration panel is also a donation link, so you can chip in to my own wedding budget if you like. 
The upcoming wedding of my fiancée and me was the inital reason of writing this plugin. 
You can read about our wedding and preparations at <a href="http://www.hasenha.us/" title="Willkommen im Hasenha.us!" rel="nofollow ugc">hasenha.us</a> 
and of course you can see the plugin in action there.

Simple Count Down

Simple configurable widgetized count down plugin.

Count All vs Simple Count Down