abedor

This plugin add metabox to a post edit page. There are you can change date of a post. The plugin works with Genesis Framework only.

Genesis Post Date

You can change date of post using this plugin

mulscully

Simply and quickly add the current date and or time to your wordpress posts by using a simple shortcode in the text of your page or post. Simply use the short code [todaysdate] in your text and when the post or page is displayed, [todaysdate] will be replaced by the current date and/or time that you defined on the settings screen.
You can also override the default format by including the format string in the shortcode.
For example, if you placed the following text in your post and your format string was set to l, F jS Y 
-> Thank you for visiting my site today [todaysdate].
The date would be displayed as 
-> Thank you for visiting my site today Wednesday, April 23rd 2014.
Here how to override he default setting by including the format string in the shortcode
[todaysdate format=”F Y”] would display April 2014 no matter what the default was set to.
This plugin also includes a Today’s date widget. This widget has it’s own default format, but can be overridden by and valid php date format string
The plugin also uses the timezone settings from wordpress to display the time and date.

Today's Date Inserter

Simply and quickly add the current date and or time to your wordpress posts or pages using a shortcode Date widget also included

Genesis Post Date vs Today's Date Inserter