Saw this on the NPS site and thought folks would be interested...
During the summer of 2005 trail work will be continuing on the subdome and shoulder portions of the Half Dome Trail. The trail will be closed during trail crew work hours from July 6 through October 4 (7:00 am-4:00 pm, Mondays-Thursdays). During this time hikers will be prohibited through this section of trail and there is no trail access to the top of Half Dome. The trail will remain open from Thursday at 4:00 pm through Monday at 7:00 am as well as after 4:00 pm until 7:00 am Monday through Wednesday.