dhruwal

This plugin is useful when you want to know what date time & timezone is it on server where wordpress is hosted if you are in other timezone. 
Output looks like:
Server Date/Time: Sat 06th Dec,2008 11:17 am 
Server Timezone: America/Phoenix, (MST -07:00)
Version Change log:
v0.5 
Supports upto WordPress 3.7.1
v0.4 
Supports upto WordPress 3.6
v0.3 
Minimize css code 
Supports upto WordPress 3.5.1
v0.2 
Added description before date time 
Added timezone information 
Changed text color from red to green
v0.1 
Initial release

WP Server Date Time

This plugin shows the server local current date time & timezone in the upper right of your admin screen on every page.

kingkode

jClocksGMT is a jQuery analog and digital world clocks plugin based on GMT offsets. 
Now supporting automatic daylight saving time conversions for affected timezones. 
Requires jQuery Rotate plugin.
<pre><code>[jclocksgmt]
</code></pre>
This shortcode will display the default clock for Greenwich, England
Additional attributes:
<ul>
<li>title
<ul>
<li>Usage <code>[jclocksgmt title='Houston, TX, USA']</code> Title of location</li>
</ul>
</li>
<li>offset
<ul>
<li>Usage <code>[jclocksgmt offset='-6']</code> Set Standard GMT offset</li>
</ul>
</li>
<li>dst
<ul>
<li>Usage <code>[jclocksgmt dst='true]</code> set FALSE if location does not need to observe dst</li>
</ul>
</li>
<li>digital
<ul>
<li>Usage <code>[jclocksgmt digital=true]</code> Display digital clock</li>
</ul>
</li>
<li>analog
<ul>
<li>Usage <code>[jclocksgmt analog=true]</code> Display analog clock</li>
</ul>
</li>
<li>timeformat
<ul>
<li>Usage <code>[jclocksgmt timeformat='hh:mm A']</code> Time format</li>
</ul>
</li>
<li>date
<ul>
<li>Usage <code>[jclocksgmt date=false]</code> Display date</li>
</ul>
</li>
<li>dateformat
<ul>
<li>Usage <code>[jclocksgmt dateformat='MM/DD/YYYY']</code> Date format</li>
</ul>
</li>
<li>skin
<ul>
<li>Usage <code>[jclocksgmt skin=1]</code> Set 1 of 5 clock themes.</li>
</ul>
</li>
</ul>
A basic shortcode for a custom location would look like this: 
 [jclocksgmt title=’Houston, TX, USA’ offset=’-6′]
See more documentation in FAQ section.

jClocksGMT World Clocks

jQuery based analog and digital world clocks for Wordpress.

WP Server Date Time vs jClocksGMT World Clocks