Disneyland in Anaheim, California, and Disney’s Magic Kingdom in Orlando, Florida, are preparing to open their parks for 24 hours straight.

First announced back in January, the 24-hour affair will be called ‘One More Disney Day.’ The 24-hour day is part of Disney’s Leap Day, 2012 celebration. Leap Day, February 29, only occurs every four years. The extra day is a way to adjust the calendar, because the earth travels around the Sun in approximately 365 days and six hours. Without Leap Day. That six hours is unaccounted for without the correction.

Disney will open the parks at 6 AM on February 29, and keep them open until 6 AM March 1. Select entertainment and attractions will continue operations all night long. According to Disney, restaurants and shops will also remain open all night, but most table service will end at midnight. There will be extra parades and shows throughout the day and night.

It’s not the first time the parks have remained open all night. They have done this before for high school graduation nights.

Disney expects large crowds, and says on their site that entry into the park will be limited “subject to capacity restrictions.”

Along with the promotion, Disney has been running a daily sweepstakes with the price each day being a Disney vacation. The sweepstakes has been running since January 1, 2012, and continues through Leap Day. Disney has posted a sign up form and rules at http://disney.go.com/memories/.