I remember in my elementary school the clocks were all synchronized to a system somewhere, presumably in the head office. The day after going back to school after a DST change the clocks would all be off by an hour and sometime in that morning they would all suddenly freeze, then fast forward or rewind an hour and then restart. In retrospect it is amusing that whomever was in charge of updating the clocks didn't do it when they first got in but waited until the school day had started.