For many people—religious and non-religious alike—Christmas Eve means hot cocoa with family, watching Love Actually, or furiously wrapping last-minute gifts. But for centuries of Jews, Christmas Eve was all about abstinence, tearing toilet paper, and the occasional poker game. Slate has a fascinating look at the little-known—even in Jewish circles—holiday of Nittel Nacht. Until recent generations, when Jewish/Christian relations smoothed out, Christmas Eve was seen by rabbis as a "day of mourning." That, combined with very real persecution, gave rise to Nittel Nacht, which started as early as the 16th century but was popularized by a Jewish mystic in the 1700s. Here are some Nittel Nacht traditions and the reasons behind them: