There are several of my twenty or so calendars that I want to be able to hide most of the time. Most of them have large numbers of schedule events that I don't want cluttering up my view of the events i want to see. If I deselect them in the calendar list under the Calendars button on the upper left of the main iCal window, they stay hidden for a day or two and then are somehow reselected and their events reappear. This same thing happens on both my iPhone 4S and my first gen iPad - all three devices are synced via iCloud - so I suppose that the problem gets passed from device to device during the sync process. In any case, I haven't been able to stop the process. Any help greatly appreciated.