Naked Pumpkin Run

The Naked Pumpkin Run (NPR) was an annual event that took place on Halloween at 11 PM. Runners would carve pumpkins into something they could wear on their head, usually with ears that doubled as handles due to the weight, and wore nothing else besides running shoes. The event appears to have started in Boulder, Colorado and happened every Halloween until 2009 when the Police Chief, Mark Beckner, decided to end it by threatening people with arrest and becoming registered sex offenders. Source: https://web.archive.org/web/20141216074152/http://www.wsj.com/articles/SB125693458626119361

The Naked Pumpkin Run also had a website which can still be seen on the Wayback Machine: https://web.archive.org/web/20120204162641/http://nakedpumpkinrun.org/home.html

According to the website, the tradition was started by Francis and Sandoval in 1999. Each year more participants would join. Source: https://web.archive.org/web/20090318155607/http://nakedpumpkinrun.org/evolution.html