Yosemite National Park will require Day Use Permits seven days per week for climbing the Half Dome cables during the summer 2011 season. Day Use Permits were required Fridays, Saturdays, Sundays, and holidays during the 2010 summer season. However, due to high volumes of people on the cables during the non permitted days, the park is instituting the seven day requirement. This is part of a two year interim program designed to address crowding on the cables that has been occurring over the past few years. https://www.nps.gov/yose/learn/news/hdpermits4.htm