In the coming weeks, millions of students will begin their fall semester of college, with all the attendant rituals of campus life: freshman orientation, registering for classes, rushing by fraternities and sororities and, in a more recent nocturnal college tradition, "pregaming" in their rooms. Pregaming is probably unfamiliar to people who went to college before the 1990s. But it is now a common practice among 18-, 19- and 20-year-old students who cannot legally buy or consume alcohol. It usually involves sitting in a dorm room or an off-campus apartment and drinking as much hard liquor as possible before heading out...