Join Porter Square Books and Tiffany Shlain at Temple Isaiah in Lexington! How can we observe Shabbat in our hectic modern world? How would it feel to unplug from technology one day a week? Emmy-nominated filmmaker, Internet pioneer, and Webby Award founder Tiffany Shlain has done just that for the past decade — a practice she and her family call “tech Shabbat.” Shlain’s new book, 24/6: The Power of Unplugging One Day a Week, takes readers on a provocative and entertaining journey…