Adam Erstelle

This plugin allows a wordpress administrator to schedule an additional css file to display on the website for holidays or special events for all visitors.
The css file will be added to the live site. Great for setting a Christmas theme!
If you just want to have a theme loaded instead of just a css file, check out the wp-scheduled-themes plugin.

WP Scheduled Styles

Schedule a css file to display on the live site for holidays or special events. (Available from Appearance - Scheduled Styles)

David Nickles

Show Date for Holiday’s Name quickly calculates and shows the full date of major U.S. holidays for the current calendar year. Add the full date notation for many U.S. Federal holidays, Hawaiian state holidays, and various cultural observances in your posts easily with just the name of the day. For federal and state public holidays that may land on a weekend, you can choose to display the actual date of the holiday or the designated observed weekday date.

Show Full Date for a Day’s Name

Add the full calendar date for many U.S. and Hawaiian holidays in your posts easily with just the name of the day.

WP Scheduled Styles vs Show Full Date for a Day’s Name