Copyright: national nude day
July 14 is National Nude Day, created as a joke public holiday by New Zealand sports show SportsCafe, which dared viewers to streak in front of then Prime Minister Helen Clark, then repeated it every year as a challenge to submit pictures and videos of viewers in the nude doing various daily activities. Although the organizers pretty much held this day somewhere between September 19 to February 6 until 2009, the internet has continued recognizing this day on July 14.
More Information
National Nude Day (Wikipedia)
National Nude Day (Days of the Year)