Last year, a group of Jewish artists and media professionals created the Sabbath Manifesto, a list of 10 principles to be followed one day a week in order to unwind. High on the list: “Avoid Technology.” The group has declared a National Day of Unplugging, from sundown on Friday, March 4, until sundown on Saturday, March 5. Even the Dunphys, on hit TV sitcom “Modern Family,” tried to go a week tech-free.