Those who have multiboot computers with the setting to change the clock in spring and fall may find, if they behave like mine, that the clock gets changed -- back an hour this weekend -- each first time you boot into a different OS. Since this is changes the motherboard clock you can end up suddenly noticing you are several hours away from reality .....
Of course I could change the Date/Time settings so that only one OS was checked but I never remember to do that either.